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MEDICAL SCHOOL 







COLLEGE OF PHARMACY 






CALIFORNIA COLLEGE 
of PHARMACY 



EXPERIMENTAL PHYSIOLOGY 
AND ANATOMY 



BY 

WALTER HOLLIS EDDY, A.M., PH.D. 
^ 

HEAD OF THE DEPARTMENT OF BIOLOGY IN THE HIGH SCHOOL OF 

COMMERCE, NEW YORK CITY, AND ASSOCIATE IN 

THE DEPARTMENT OF BIOCHEMISTRY 

COLUMBIA UNIVERSITY 



Qallfcrnla CoHe^a of Pharmacy 



REVISED EDITION 



NEW YORK I CINCINNATI : CHICAGO 

AMERICAN BOOK COMPANY 

* 



COPYRIGHT, 1906, 1911, BY 
WALTER HOLLIS EDDY 



Eddy's Experimental Physiology 
w. P. 4 



PREFACE 



THOUGH the importance of Physiology in secondary schools 
is everywhere recognized, little attempt has been made to 
place the subject on an experimental basis. The recent 
great advances in physiological chemistry have directed the 
attention to the possibilities of the experimental method as 
a means of investigating the principles of the subject. This 
book represents a selection of experimental matter which 
is adapted to the age of elementary students of the subject 
and which, at the same time, will present the facts of physi- 
ology in a concrete form. 

The starred topics in the following table of contents con- 
stitute a brief course covering that which is most essential; 
and the optional exercises make it possible to extend the work 
at the discretion of the teacher. 1 The ingenuity of the 
teacher will readily suggest substitutes for the material 
suggested when the laboratory facilities of the school are 
inadequate. 

Some of the exercises may be made demonstrations, and 
time in school may be saved by assigning some of the simpler 
exercises as part of the home work of the pupil. 

In the present edition several changes have been made, 
based partly on experience gained in teaching the first edition 
and partly on the advance in scientific knowledge of the 

1 The book in its starred topics meets the requirements of the New 
York State Syllabus, and as a whole has been accepted by the Harvard 
College authorities as meeting the entrance requirements of that Insti- 
tution. 



4 PREFACE 

subject. It has been found, for example, that certain phases 
of elementary chemistry need emphasis for proper appreci- 
ation of later phases of pure physiology. To that end, exer- 
cises on chemical and physical change, and on mixtures and 
solutions have been introduced. Again, new reagents have 
been devised to facilitate various tests; for example, the Bene- 
dict solution in place of the less stable Fehling's solution, and 
the biuret reagent, which does away with the complicated pro- 
cedure for the biuret test for protein. The collodion bag 
dialyzer is another laboratory device which has simplified the 
teaching of osmosis and has accelerated the process so that 
with it osmotic pressures may be obtained in twenty minutes 
that formerly required some hours. The wording of many 
experiments has been altered and the procedure shortened 
and simplified to enable the principle to be more readily 
grasped. For example, in the digestion experiments the 
work has been rearranged in such a way as to separate 
the determination of the conditions for digestion from the 
mere process of digestion and thus permit the pupil to 
reach the conclusions separately and with added emphasis 
and clarity. The recent changes in our views as to the nature 
of fat digestion and the action of bile are also developed in 
new forms of experiment, and this change typifies another 
form of improvement in the present edition. 

I wish to acknowledge again the many helpful suggestions 
given me by my colleagues of the High School of Commerce 
and by others in various parts of the country who have 
called my attention to faults in the earlier edition. To Dr. E. 
A. Darling of Harvard College and to Mr. Frank 0. Payne of 
the High School of Commerce I am especially indebted for 
their aid and critical review of the manuscript of the first 
edition. Many of the improvements in methods and labora- 
tory devices I owe directly to my association with and to 



PREFACE 5 

suggestions from Professor William J. Gies of the Columbia 
University Department of Biological Chemistry, notably the 
collodion bag dialyzer and the biuret reagent. To Dr. Stanley 
R. Benedict I beg to give credit for the solution which 
bears his name. To Mr. C. W. Harm, my colleague in the 
High School of Commerce, I am also indebted for valuable 
suggestions based upon teaching experiments with the first 
edition. Finally, I wish to acknowledge my debt to my wife 
for assistance in many details of grammatical arrangement 
and mechanical labor involved in the work. 

WALTER H. EDDY. 

THE HIGH SCHOOL OF COMMERCE, 
NEW YORK. 



METHOD OF EXPEKIMENT 



IT has been my purpose so to state each of the following 
exercises as to admit of its performance by the pupil with 
a minimum amount of direction from the teacher. Most 
of the exercises should be thus performed by each pupil 
individually, or by two pupils together; but of course the 
teacher may select as many as desired for performance as 
demonstrations before the class. 

It is essential that each pupil make a suitable record of 
all exercises performed, in a carefully prepared notebook. 
It is recommended that a separate-leaf notebook be used 
for this purpose, as this makes possible the inspection of 
one set of exercises without handling the entire books, and 
permits the rewriting of unsatisfactory work without dis- 
turbing the arrangement of the book. 

It is generally agreed, too, that the book should consist 
of original reports made at the time of experiment, and not 
of matter copied from original rough drafts. 

Frequent examination of all laboratory notes by the 
teacher is also essential to good work, and the proper status 
of the notebook work can be secured only by giving it a 
definite proportion in the marking of the pupil's work. 
A rubber stamp with the word " Approved" and the in- 
structor's name may be obtained of any stationer at small 
expense and wi 1 ! greatly facilitate the work of correction. 
Neatness as well as accuracy and adequacy of report should 
receive proper weight in the marking of notebook work. 

7 



8 METHOD OF EXPERIMENT 

When the work is completed the student should prepare 
an index of drawings, records of experiments, and descrip- 
tions of demonstrations contained in the notebook. It is 
well to indicate in this index, after each title, whether the 
work was done by the pupil or observed and recorded by 
him, and whether in the laboratory or as home work. 

The following directions may prove of value as indicating 
a satisfactory method of arrangement of a notebook record: 

A. Record the number and date of the exercise. 

B. Make drawings of the apparatus used, when neces- 

sary, and label them properly. 

C. State as briefly as possible: 

(1) What was done. 

(2) What happened as the result of (1). 

(3) What meaning these results have, and the 

purpose of the exercise. 

D. Answer all questions in the text and try to con- 

dense your statements into as concise and brief 
a form as possible. 

The exercises as a rule should precede the text study and 
serve as a basis for such study. 



TABLE OF CONTENTS 



Required topics are indicated by a star (*) ; the others are optional. 
PRELIMINARY EXERCISES 

BXERCISB PAGE 

I. GLASS BENDING AND CUTTING 13 

II. COLLECTION OF GASES 14 

INTRODUCTORY EXERCISES IN PHYSICS AND CHEMISTRY 

III. CHEMICAL CHANGE 16 

IV. PHYSICAL CHANGE 16 

V. MIXTURES AND SOLUTIONS 17 

*VI. PROPERTIES OF PHOSPHORUS 18 

*VII. PROPERTIES OF SULPHUR 18 

*VIII. PROPERTIES OF CARBON 19 

*IX. PROPERTIES OF IRON 21 

*X. OXYGEN AND OXIDATION 21 

*XI. PROPERTIES OF OXYGEN 23 

*XII. COMPOSITION OF AIR AND PROPERTIES OF NITROGEN.. 25 

XIII. COMPOSITION OF WATER 26 

XIV. PROPERTIES OF HYDROGEN 28 

*XV. ACIDS, BASES, SALTS, AND NEUTRALIZATION 29 

STUDY OF NUTRIENTS 

*XVL PROTEINS 31 

*XVII. CARBOHYDRATES STARCH 33 

*XVIII. CARBOHYDRATES GRAPE SUGAR (GLUCOSE) AND CANE 

SUGAR (SUCROSE) 33 

*XIX. FATS AND OILS 34 

XX. MINERAL SALTS 35 

XXI. WATER 36 

STUDY OF FOODS 

*XXII. NECESSITY OF FOOD 37 

*XXIII. NUTRIENTS PRESENT IN COMMON FOODS 38 

*XXIV. STUDY OF FOOD CHARTS 39 

9 



10 



TABLE OF CONTENTS 



HlSTOLOGICAL STUDIES 



EXERCISE PAGE 

*XXV. PARTS OF A CELL 41 

*XXVI. STUDY OF A PLANT CELL 42 

*XXVII. STUDY OF LIVING PROTOPLASM AMCEBA 43 

XXVIII. EPITHELIAL TISSUE 47 

XXIX. CONNECTIVE TISSUE 48 

XXX. MUSCULAR TISSUE 50 

XXXI. NERVOUS TISSUE 51 

PRINCIPLES OF DIGESTION 

*XXXII. PRINCIPLES OF OSMOSIS 52 

*XXXIII. AN ENZYME 54 

*XXXIV. A FERMENT ORGANISM YEAST 56 

*XXXV. STRUCTURE OF A TYPICAL GLAND 57 

ORGANS AND PROCESSES OF DIGESTION 

*XXXVI. DISSECTION OF RAT'S DIGESTIVE ORGANS 58 

*XXXVII. THE TEETH 60 

XXXVIII. PREPARATION OF DIGESTIVE FLUIDS 62 

*XXXIX. SALIVARY DIGESTION 63 

*XL. PEPTIC DIGESTION 66 

*XLI. PANCREATIC DIGESTION 68 

*XLIL STUDY OF DIGESTIVE ACTION OF BILE 69 

XLIII. MICROSCOPIC ANATOMY OF THE DIGESTIVE TRACT. . . 70 

XLIV. TABULATION OF NUTRIENT DIGESTION 71 

BLOOD 

*XLV. GENERAL PROPERTIES OF BLOOD 72 

*XLVI. STUDY OF Ox OR HOG BLOOD 74 

XLVII. CRYSTALLIZATION OF HAEMOGLOBIN FROM BLOOD 76 

XLVIII. DETECTION OF BLOOD IN BLOOD STAINS 76 

CIRCULATION AND THE BLOOD SYSTEM 

*XLIX. PROPERTIES AND LOCATION OF ARTERIES AND VEINS . . 78 

*L. CIRCULATION IN A FROG'S FOOT 79 

LI. MINUTE STRUCTURE OF ARTERIES AND VEINS 80 

*LII. STRUCTURE OF THE HEART 81 



COLLEGE 

TABLE OF CONTENDS 



11 



THE BODY SKELETON 

EXERCISE PAGE 

*LIII. STUDY OF THE SKELETON 86 

*LIV. GROSS STRUCTURE OF BONES 86 

LV. COMPOSITION OF BONE 88 

*LVI. STRUCTURE OF A JOINT 88 

*LVII. FORMS OF JOINTS 89 

MUSCLES AND MOTION 

*LVIII. DISSECTION OF THE MUSCLES 90 

*LIX. GROSS STRUCTURE OF MUSCLE 91 

LX. NERVE MUSCLE PREPARATION 91 

LXI. STUDY OF LEVER ACTION 93 

LXII. LEVERS OF THE BODY 94 

RESPIRATION 

*LXIII. DISSECTION OF A RAT'S LUNGS 96 

*LXIV. MECHANICS OF RESPIRATION 97 

*LXV. STUDY OF EXPIRED AIR 98 

EXCRETION 

LXVI. STUDY OF A LAMB'S KIDNEY 99 

*LXVII. STUDY OF THE SKIN 100 

NERVOUS SYSTEM 

*LXVIII. DISSECTION OF SHEEP'S BRAIN 103 

*LXIX. DISSECTION OF SPINAL CORD 107 

SPECIAL SENSES 

*LXX. NERVE ACTION 109 

*LXXI. CUTANEOUS SENSATIONS 109 

*LXXII. STUDY OF THE TONGUE 110 

*LXXIII. SENSATIONS OF TASTE AND SMELL 110 

LXXIV. HEARING; LAWS OF SOUND Ill 

*LXXV. VISION; DISSECTION OF SHEEP'S EYE 112 

*LXXVI. ACTION OF THE EYE 114 

BACTERIA 

"LXXVIL STUDY OF BACTERIA. . 117 



EXPEEIMENTAL PHYSIOLOGY 
AND ANATOMY 



PRELIMINARY EXERCISES 



I. GLASS BENDING AND CUTTING (OPTIONAL) 

Apparatus. Several pieces of quarter-inch, glass tubing about two 
feet in length, a three-cornered file, a Bunsen burner with fishtail 
attachment. 

Directions. A. Bending. Place the fishtail attach- 
ment on the burner and light the gas. Hold at the ends 
the tube which is to be bent and bring into the flame the 






Fio. 1. 

part at which you wish the bend (see Fig. 1). Turn the 
tube constantly to insure equal heating of all parts, and 
when the glass is flexible remove from the flame and bend 
the two ends slowly toward each other until the desired 
angle is obtained. Use care to keep the two ends in the 
same plane, and do not bend quickly, as that would cause 

13 



la PRELIMINARY EXERCISES 

buckling. If the glass cools too soon return it to the flame 
and treat as before. 

B. Cutting. Wet the file and, holding the tube firmly 
with finger and thumb, make a slight scratch across it. 
Turn the tube over and repeat the operation at a point 
directly opposite. Now grasp the tube in both hands, one 
on each side of the scratches, and bend sharply. The result 
should be a clean, square-ended break. The edges may be 
rounded by holding them in the flame a moment. 



II. COLLECTION OF GASES (OPTIONAL) 

Apparatus. Pneumatic trough and support, glass tube bent at 
right angles, large-mouthed bottles, piece of glass to cover mouth of 
bottle. 



Directions. A. Fill the trough with water to the depth 

of a half inch above the 
top of the support. Fill 
the bottle with water, 
cover the mouth with 
the glass, and invert, 
putting the mouth under 
the water of the trough. 
Remove the piece of 
glass, and place the bot- 
tle over one of the holes 
of the support. Does 
the water flow out? Ex- 
plain. 

Now introduce the 





FIG. 2. 



short end of the glass 
tube into the mouth of the bottle (see Fig. 2) and blow 



PRELIMINARY EXERCISES 15 

through the other end. Where does this gas go? Why? 
Would this method of collecting gases be successful if they 
were readily soluble in water? 

B. Fill a second bottle with water and invert in the same 
way as the first. Bring the one containing the gas under 




FIG. 8. 



the one containing the water, and gradually turn it mouth 
upward (see Fig. 3). In this way gases may be transferred 
from one vessel to another for study. 



INTRODUCTORY EXERCISES IN PHYSICS 
AND CHEMISTRY 



III. CHEMICAL CHANGE (OPTIONAL) 

Apparatus. Powdered sulphur, test tube, strip of copper foil, 
Bunsen burner. 

Directions. Examine the sulphur and copper foil care- 
fully and write a description of each, stating the character- 
istic features of each substance. 

Next, place a strip of copper foil an inch long in the test 
tube and cover to the depth of a quarter inch with powdered 
sulphur. Heat the tube in the flame of the lamp and note 
every change that takes place. State the changes that 
take place in the sulphur in the order of their occurrence. 
State what happens to the copper. When no further change 
occurs, remove the strip from the tube and examine it care- 
fully. Does it bend easily? Is it the color of copper? 
Can you find any sulphur? Is the strip copper? Sulphur? 
Give reasons for your statement. Changes that result in a 
new substance with new properties are called chemical 
changes. Write a statement giving your opinion as to 
whether this was a chemical change and include in this 
statement your reasons for your conclusion. 

IV. PHYSICAL CHANGE (OPTIONAL) 

Apparatus. Ice, chemical thermometer, beaker, tripod, Bunsen 
burner. 

Directions. Place several pieces of ice in the beaker 
and stir it about with the thermometer. Note the tempera- 

16 



PHYSICS AND CHEMISTRY 17 

ture of the ice. Next, light the burner and heat the ice 
gently. What happens to the ice? Does the temperature 
rise? Was this change in the ice like that of the sulphur or 
copper? Reason for your answer. 

Continue the heating until the temperature rises no 
further. What is the reading at this point? What change 
is taking place? Is it a chemical change? Reasons for 
answer. 

Write a statement comparing the changes observed in 
Exercises III and IV and explain the differences between 
them. 

V. MIXTURES AND SOLUTIONS (OPTIONAL) 

Apparatus. Powdered chalk, table salt, water, 4 beakers, 2 fun- 
nels, filter paper, 2 evaporating dishes, 2 Bunsen burners. 

Directions. A. Fill a beaker half full of water and 
stir into it a teaspoonful of powdered chalk. What appear- 
ance has the water? Fit a filter paper into a funnel and pour 
half of the chalk and water mixture through the filter into 
the second beaker. Compare the filtered and unfiltered 
portions. Pour half the filtered portion into an evaporating 
dish and evaporate to dryness. Is any residue left in the 
dish? 

B. Repeat the steps given in A with the rest of the 
apparatus, but substitute a teaspoonful of salt for the chalk. 
Record the results as in A. 

C. Compare the results of A and B and from your com- 
parison answer these questions: (a) Does chalk dissolve 
in water? (6) Does salt? (c) How can you demonstrate 
the solubility or insolubility of any substance? 



18 EXPERIMENTAL PHYSIOLOGY 

X VI. PROPERTIES OF PHOSPHORUS 

Apparatus. Piece of yellow phosphorus, evaporating dish, forceps, 
knife. 

Directions. (Caution! Phosphorus should be kept un- 
der water and cut under water. It should not be allowed 
to come in contact with the bare skin.) 

Fill the evaporating dish with water and with the forceps 
place the piece of phosphorus in it. With the knife cut off 
a piece and examine the cut surface. Does it cut easily? 
What color is the new cut surface? Leave this exposed to 
the light for a time, keeping it under water, and note any 
change in color. Is phosphorus soluble in water? 1u- 

Pick up a piece with the forceps, wipe dry with filter or 
blotting paper, and hold in the air a moment. Describe 
what takes place. Why is phosphorus kept under water? 
Does phosphorus give off any odor? 

Rub phosphorus gently ori a piece of paper and examine 
the paper afterwards in the dark. What evidence have you 
that phosphorus burns at a low temperature? 

(Bone and brain are the parts of the body richest in phos- 
phorus.) 

Make a list of the properties of phosphorus so far as you 
have observed them. 

VII. PROPERTIES OF SULPHUR 

Apparatus. Half a teaspoonful of flowers of sulphur or a piece 
of stick sulphur, a silver spoon, a hard-boiled egg, a raw egg, an 
evaporating dish, alcohol lamp or Bunsen burner. 

Directions. Examine a little of the sulphur. Describe 
its odor, taste, color. Shake some up in water. Does it 
dissolve? 



*ARMACY 

PHYSICS AND CHEMISTRY 19 

Place a little in the dry evaporating dish and heat gently. 
Does it melt? Describe its condition*. Continue to heat, 
and describe the various changes through which it passes.. 

Touch a match to a little dry sulphur. Does it burn? 
Describe the result. Smell of the. fumes (Caution!). Where 
have you noticed this odor before? (This odor is due to 
a gas called sulphur dioxide and this gas is formed whenever 
sulphur is burned.) 

Place a little of the sulphur in the bowl of the silver 
spoon. After a moment brush it off. Is the silver still 
bright? (When silver is brought in contact with sulphur 
the latter unites with it and forms a compound called silver 
sulphide, which is black.) 

Mince the hard-boiled egg with the handle of the silver 
spoon. What happens? Compare with above result. Eggs 
contain sulphur. 

Place the raw egg in a clean evaporating dish and leave 
in a warm place for several days. 1 When the egg decays 
note the odor. (This odor is due to another compound of 
sulphur called hydrogen sulphide. When animal flesh decays 
it gives off this odor, showing that flesh contains sulphur.) 

Mention seven properties of sulphur which you have ob- 
served in the above experiments. 

/ 
VIII. PROPERTIES OF CARBON 

Apparatus. Stick of wood charcoal, bottle with a small mouth, 
limewater, 2 glass tube six or eight inches long, beaker, test tubes, 
splinter of wood, pieces of meat, piece of marble, hydrochloric acid. 

1 It is Well to place the dish in a closed vessel containing a little water, as 
otherwise the egg may dry up without decaying. 

2 Limewater may be made by shaking a little quicklime in water, allow- 
ing the mixture to settle and decanting the clear liquid. 



20 EXPERIMENTAL PHYSIOLOGY 

Directions. Examine the charcoal stick. (Charcoal is 
one of the forms of carbon.) Describe its color, odor, taste. 
Does it dissolve in water? 

Light the stick, after trimming it to such a size as to enable 
it to be thrust through the neck of the bottle. Does it give 
off any odor in burning? Is it like or unlike sulphur in this 
respect? 

Thrust the lighted stick of charcoal into the bottle and 
keep it there until the flame goes out. Now remove it and 
cover the mouth of the bottle with the finger. Can you see 
anything in the bottle? Pour a little clear lime water into 
the bottle and shake the bottle. What happens to the color 
of the lime water? What sort of substance must be present 
in the bottler (When carbon burns it forms a gaseous 
compound with the oxygen of the air called carbon dioxide. 
This gas is the only one that will cause the change in lime- 
water noted above.) 

Rinse out the bottle with water. Light the wood splinter 
and thrust into the bottle. Proceed as with the charcoal. 
Test the contents of the bottle with limewater. What 
evidence have you that wood contains carbon? 

Burn the piece of meat by heating it in the test tube. 
Pour limewater into the tube. What evidence have you 
that animal flesh contains carbon? 

Place the piece of marble in a clean test tube. Pour on it 
a little hydrochloric acid which has been diluted previously 
with twice its volume of water. What evidence of action have 
you? Suspend a drop of limewater in the mouth of the tube. 
Hydrochloric acid and water contain no carbon; what must 
you conclude as to the presence of carbon in the marble? 

(Carbon is to be found in all animal and vegetable com- 
pounds and in some minerals.) 



PHYSICS AND CHEMISTRY 21 

Pour some of the limewater into the beaker. By means 
of the glass tube blow some of your breath through the 
liquid in the beaker. In what form is the carbon in your 
breath? (Expired air contains about 4 parts of this gas in 
every 100 parts of the expired air. Ordinary air contains 
about .04 part of this gas in 100 parts, or about 4 parts in 
every 10,000 parts of air.) 

(Besides charcoal, the other forms of carbon are diamond 
and graphite. All the forms of carbon are odorless, taste- 
less, and insoluble in water; and if strongly heated in the 
presence of oxygen, each form of carbon will combine with 
it and form carbon dioxide.) 

IX. PROPERTIES OF IRON 

Apparatus. Several feet of fine wrought-iron wire, a magnet, an 
evaporating dish. 

Directions. Bring the magnet in contact with the iron. 
Raise the magnet. Note the result. See if other things 
act similarly toward the magnet. 

Place a coil of the wire in a warm, dry place. Place a like 
coil in the evaporating dish and cover with water. Leave 
both coils for several days, and then examine them. Note 
any differences between the two coils. What conditions are 
favorable to this change? (Rust is a compound that iron 
forms with the oxygen of air and water. It is this power 
of iron to unite with oxygen that makes it valuable as a 
part of the blood in the animal body; see Exercise XL VI, 
last paragraph.) 

' X. OXYGEN AND OXIDATION 

Apparatus. Red oxide of mercury (mercuric oxide), test tube, 
stick of charcoal, limewater and glass tube, Bunsen burner. 

Directions. Place in a test tube as much red oxide as 
you can get on your finger nail. Heat the test tube in the 




22 EXPERIMENTAL PHYSIOLOGY 

flame (see Fig. 4.) 1 Heat the end of the charcoal stick until 
it glows, and introduce it into the mouth of the test tube. 
After heating the oxide hot you will notice 
a change in the glow of the charcoal. De- 
scribe it. Can you see anything in the 
tube? If it be a colorless gas that is act- 
ing on the charcoal can that gas be air? 
Reasons for your statement. 

Remove the tube from the flame. When 
the stick ceases to glow remove it and 
substitute for it a drop of limewater on the 
end of the glass tube. What happens? What does this in- 
dicate? As the tube cools what do you see on the sides of 
the tube? Do you know the name of this substance? 

EXPLANATION. Oxide of mercury is a compound of mer- 
cury (quicksilver) and oxygen. Heat decomposes this into 
oxygen and mercury. In what form were these two sub- 
stances given off in the above experiment? We have al- 
ready learned that when charcoal burns it forms % a gas called 
carbon dioxide. How was this gas formed in the above exer- 
cise? We can express the above actions in the form of 
equations as follows: 

(1) Oxide of mercury = oxygen and mercury. 

(2) Oxygen + carbon = oxide of carbon. 

In chemical language the process illustrated in (1) is 
analysis, or the separation of a compound into its parts. 
The process illustrated in (2) is synthesis, or the union of 
parts to make a compound. All chemical actions may be 
grouped under one or the other of these processes. 

The special kind of compound that results from the union 

1 The flame of an alcohol lamp is not hot enough to produce the changes 
described in this experiment. 



PHYSICS AND CHEMISTRY 23 

of oxygen with a substance is called a compound of oxida- 
tion, and the actual formation is called oxidation. When 
oxidation takes place rapidly, light and heat are produced 
at the same time and the process is called rapid oxidation 
or combustion. Give examples from your experience of both 
kinds of oxidation the slow and the rapid. Why does the 
exclusion of air from a fire cause the fire to go out? What 
is the precise action of water or sand when thrown on a 
flame, in the light of the above explanation? Write a full 
statement of what took place in the above experiment. 

XI. PROPERTIES OF OXYGEN 

Apparatus. Chlorate of potash (potassium chlorate), manganese 
dioxide, piece of phosphorus, stick of charcoal, sulphur, fine iron wire, 
Florence flask, one-holed rubber stopper, rubber and glass connect- 
ing tubing, wash bottle fitted with two-holed stopper, ring stand, 
sand bath, pneumatic trough, five large-mouthed glass bottles with 
glass plates to cover, caustic soda, Bunsen burner or alcohol lamp, 
deflagrating spoon. 

Directions. Set up the apparatus as in Fig. 5. Place 
in the flask to a depth of half an inch a mixture of one part 
of manganese dioxide to four parts of chlorate of potash. 
Fill the wash bottle about half full of water and dissolve 
a stick of caustic soda in it. 1 When everything is connected 
as in the diagram heat the flask gently on the sand bath. 
The first of the gas produced will mix with the air in 
the apparatus and should be allowed to escape. When the 
bubbles of gas flow freely through the delivery tube, fill 
one of the bottles with water and invert over the delivery 
tube to receive the gas (oxygen) as in the above diagram 
(see Exercise II on page 14). When the bottle is full cover 
with the glass plate and set aside, mouth upward. Fill 
1 This will absorb the impurities in the oxygen. 



24 



EXPERIMENTAL PHYSIOLOGY 



the other four bottles in the same way. Then proceed as 
follows: 

A. Examine the gas in the first bottle. Describe its color 
and odor. Suck a little into the mouth with a glass tube. 
Has it any taste? 

B. Tie a piece of charcoal to the handle of the deflagrat- 
ing spoon, heat the end of the charcoal until it glows, and 




FIG. 5. 

introduce it into the second bottle. Describe the result. 
Keep lowering the charcoal as it tends to stop burning, until 
it reaches the bottom of the bottle. Compare this result 
with that of Ex. X. What name do you give to this process? 
How could you test the contents of the bottle to prove your 
statement? Do so and record result (see Ex. VIII). 

C. Place in the bowl of the deflagrating spoon a piece 
of phosphorus the size of a pea (Caution! Handle with 
forceps and cut under water.) Light the phosphorus and 
introduce quickly into the third bottle. Describe the result. 



PHYSICS AND CHEMISTRY 25 

Does it burn more or less brilliantly than in air? Note the 
white cloud in the bottle. (This is an oxide of phosphorus 
and is formed by the uniting of the phosphorus and the 
oxygen.) Compare this result with that in B. 

D. After cleaning the deflagrating spoon place some pow- 
dered sulphur in it. Light the sulphur. Note how it burns 
in air and the color of the flame. Now introduce it 

into the fourth bottle. Describe the result. After the 
burning is over smell (Caution!) the gas in the bottle. 
Compare with the odor of burning sulphur in Ex. VII. 
What is the name of this gas? Is the action noted 
above combustion? Give your reasons. (See Ex. X.) 

E. Heat the end of the fine iron wire red hot and 
introduce it into the fifth bottle. Describe the result. 
After the action is over examine, the red spots on the 
sides of the bottle and compare them with the rust 
obtained in Ex. IX. What is the difference between FIG. 6. 
the two actions? 

Name the properties of oxygen that you have observed. 

XII. COMPOSITION OF AIR AND PROPERTIES OF 
NITROGEN 

Apparatus. Pneumatic trough, bell jar closed at the top, evap- 
orating dish, test tube, phosphorus. 

Directions. Fill the pneumatic trough so as just to cover 
the support. Place the evaporating dish on the support. 
Place in it a piece of phosphorus the size of a pea; light the 
phosphorus, and cover quickly with the bell jar. 

A. Note the white fumes that appear. What are these? 
(See Ex. XI, C.) What is one of the components of air? 
When the jar is first put on, note that some bubbles are forced 
out because the heat causes the air to expand a little. The 



26 



EXPERIMENTAL PHYSIOLOGY 






FIG. 7. 



phosphorus stops burning when all the oxygen in the bell 

jar is used up. Let the apparatus 
stand until the white oxide of phos- 
phorus has been absorbed by the 
water and the gas in the jar is clear. 
(Phosphorus was used instead of 
sulphur or charcoal in this exer- 
cise because its oxide is a solid 
which settles and dissolves in the 
water.) Has the water risen in 
the jar? What part, by volume, 
of the jar does it occupy? Since 
the phosphorus has used up all the oxygen in burning, about 
what part of air must be oxygen? 

B. Fill the test tube with gas from the bell jar in the 
manner described in Ex. II, B. Examine this gas. De- 
scribe its color, odor, taste. Place a lighted match in it. 
What happens? Explain. (This gas is called nitrogen. 1 ) 
Of what advantage is the presence of nitrogen in the air? 
Why is a good draft necessary to make a fire burn freely? 
If the body needs to take in oxygen constantly why can we 
not live in a sealed room? Compare the properties of 
nitrogen, air, and oxygen. 

XIII. COMPOSITION OF WATER (OPTIONAL) 

Apparatus. Electrolysis apparatus, 2 sulphuric acid, four dry 
cells, splinters of wood, test tubes, pneumatic trough or other dish 
of water, glass and rubber connecting tubing. 

1 Other gases (carbon dioxide, argon, water vapor) are present in very 
small proportions. 

2 For the electrolysis apparatus shown on p. 27 may be substituted 
simpler forms with nearly as good results. Simple forms are shown in 
Clark and Dennis's " Elementary Chemistry," page 33, and in Remsen's 
" Chemistry, Briefer Course." 



PHYSICS AND CHEMISTRY 



27 




Directions. Open the two stopcocks and fill the ap- 
paratus with water containing 5 per cent of sulphuric acid. 
When the tubes are full and all air is 
driven out, close the cocks; arrange the 
four dry cells in series (positive pole of 
one connected with negative pole of the 
next, and so on), and connect the pos- 
itive and negative poles of the series 
with the posts as indicated in Fig. 8. 
Note what happens. Where do the 
bubbles form? In which tube do they 
form most rapidly? What is the ratio 
by volume of the gases in the two tubes? 
When the tube containing the most 
gas is full, disconnect the cells. Collect 
in a test tube the gas from the tube con- 
taining the lesser amount as follows: 
With rubber tubing connect an ordinary 
delivery tube, filled with water, to the top of the gas tube. 
Insert the end of the delivery tube into the mouth of the 

test tube, after filling the 
test tube with water and 
inverting, as in Ex. II. 
Open the cock and col- 
lect the gas, as in Fig. 9. 
Cover the mouth of the 
tube with the thumb and 
hold it mouth upward. 
FlG - 9 * Now remove the thumb 

and quickly insert a lighted splinter into this collected gas. 
What happens? What gas have you studied that produces 
a similar action? This is the same gas. 




FIG. 8. 




28 



EXPERIMENTAL PHYSIOLOGY 



In a second test tube collect the gas in the other tube. 
Hold it mouth downward, and introduce a lighted splinter 
into it. Describe what happens. How is this gas different 
from oxygen? from nitrogen? (The name of this new gas 
is hydrogen. The electric current has dissociated the com- 
pound water into two parts hydrogen and oxygen.) 
Is this exercise synthesis or analysis? 

XIV. PROPERTIES OF HYDROGEN (OPTIONAL) 

Apparatus. Granulated zinc or pieces of sheet zinc, dilute sul- 
phuric acid, 1 bottle with two-holed stopper, thistle tube, glass and 
rubber connecting tubing, pneumatic trough, large-mouthed bottle, 
test tubes. 

Directions. Set up the apparatus as in the diagram. 
Place a handful of zinc in the bottle and pour on enough 

dilute sulphuric acid through 
the thistle tube to cover the 
zinc. (Caution! Keep all 
flames away from the appa- 
ratus until the gas is col- 
lected.) Let this gas escape 
until it is bubbling freely 
from the delivery tube; then 
collect the large bottle full, 
through water, as in Ex. XI. 2 
A. By the method of Ex. 
II, B, take some of the gas in a test tube and examine it, 
holding the test tube mouth downward. Describe its color, 
odor, taste. 

1 To dilute sulphuric acid, pour slowly one part of concentrated acid 
into five or six parts of water. Stir while pouring. 

2 The gas will be freer of impurities if passed through a wash bottle 
containing permanganate solution. 




FIG. 10. 



PHYSICS AND CHEMISTRY 29 

B. Collect a second test tube full and hold mouth down- 
ward as before. Tie a match to a wire, light the match, and 
thrust it up into the tube. Does the match continue to 
burn? Reason? Where does the hydrogen burn? Why? 
After the hydrogen has burned up, examine the sides of 
the tube. What do you find on them? Why should you 
expect this? What is oxide of hydrogen? 

C. Hold a fresh tube full of hydrogen mouth upward 
for a few moments. At the end of that time test with a 
match. Is the hydrogen still there? Explain. (Hydro- 
gen is the lightest substance known.) Make a list of the 
properties of hydrogen. 

XV. ACIDS, BASES, SALTS, AND NEUTRALIZATION. 

Apparatus. Dilute hydrochloric and nitric acids (one part acid 
to ten parts water), caustic soda, red and blue litmus paper, evapo- 
rating dish, glass stirring rod, Bunsen burner. 

Directions. A. Examine some of the dilute hydrochloric 
acid. What sort of odor has it? Describe its taste. Rub 
some between the fingers; describe its " feel." Dip a piece 
of red litmus into it. What is the effect? Dip in a piece 
of blue litmus. Describe the result. (The taste, " feel/' 
and effect on litmus noted are three ways in which to 
detect an acid.) Test some common substances with red 
and with blue litmus and record results; e.g., cream of 
tartar, vinegar, soda, fruit juices, ammonia. 

B. Dissolve a stick of caustic soda, an inch long, in a 
tumbler of water. Examine this liquid. What is its taste? 
odor? " feel "? Te&t it with the two kinds of litmus paper 
and record results. (This kind of substance is called a base. 
Bases always react in this way to taste, ( ' feel/' and litmus. 



30 EXPERIMENTAL PHYSIOLOGY 

Certain strong bases are called alkalis.) Test the substances 
named in A. Which of these are bases? 

C. Pour some of the caustic soda solution into the evap- 
orating dish. Add, gradually, the dilute hydrochloric acid, 
stirring with the rod and testing with the litmus until the 
solution turns neither red litmus blue nor blue litmus red. 
If too much acid is added correct it with more basic solu- 
tion. The acid and the base are now said to be neutralized, 
and the process is called neutralization. Evaporate this 
mixture to dryness over the flame. What sort of substance 
is left in the dish? Taste it. Is it familiar? Does it affect 
litmus in the solid state or when dissolved in water? 

D. Repeat the above neutralization, using nitric acid in- 
stead of hydrochloric. Does the product affect litmus? 

(The products of C and D are called neutral salts. To this 
class of substances belong most of the minerals of the earth.) 
This exercise may be continued with other acids and bases 
at the desire of the experimenter. 



STUDY OF NUTRIENTS 



Phosphorus, sulphur, carbon, iron, oxygen, nitrogen, and 
hydrogen are a few of the chemical elements to be found in 
plant and animal bodies. These elements occur, however, 
not as elements, but in combinations, or compounds. There 
are many of these combinations, but they may be grouped 
together under a few class names. These classes of com- 
pounds show certain definite qualities by means of which 
their presence may be detected. The classes are called proxi- 
mate principles, or nutrients. The most important are: 

Proteins, or nitrogenous compounds. 1 

Carbohydrates, or starches and sugars. 

Fats and oils. 

Mineral salts. 

Water. 

XVI. PROTEINS 

Apparatus. Raw white of egg, olive oil, salt, nitric acid, ammonia, 
Millon's reagent, 2 Biuret reagent, 3 test tubes. 

Directions. A . Put a little raw white of egg (a good 
example of protein) in a test tube, cover with two inches 
of water, and shake. Does the white of egg dissolve? 
Shake the mixture and note the result. Heat the water 

1 The American Biochemical Association has revised its nomenclature 
and agreed upon the use of the word protein to designate this class of 
compounds, restricting the word proteid to a definite group under the 
general class of proteins. 

2 To make Millon's reagent, mix one part of mercury by weight with 
two parts of nitric acid (concentrated commercial) : when the mercury is all 
dissolved, dilute with twice the volume of water. 

3 To make biuret reagent, make first 1000 c.c. of 20 per cent solu- 
tion of caustic soda in water. Then to this add (a few drops at a time 
with constant stirring) 10 c.c. of 3 per cent copper-sulphate solution. 

31 



32 EXPERIMENTAL PHYSIOLOGY 

and egg mixture slowly. What form does the white of egg 
take now?^-5g^bhis form soluble in water? ^x^> 

Put a second portion of the egg in a test tube. Add 
dilute nitric, acid to it. What happens to the white of 
egg? ' Compare the action with that in boiling water. &-~ 

(This action of acid and heat on a protein like egg albu- 
min is called coagulation.) Why does a piece of meat (which 
is composed mainly of a protein like white of egg) become 
more solid under heat? *z*^-*^&+~ 

B. Xanthoproteic Test. Place a little coagulated white of 
egg in a test tube and cover with dilute nitric acid. Heat 
to boiling, and then add enough .ammonia to neutralize the 
acid and give an alkaline test. The white of egg (protein) 
takes what color? Treat in the same way some olive oil, 
some common salt, and any other substance that does not 
contain protein. Do any of these take the same color as 
the white of egg? 

C. Millon's Test. Add enough Millon's reagent to a little 
coagulated white of egg to cover, and raise the temperature 
gradually by holding the test tube several inches above the 
flame. What color does the egg and the solution become? 
Treat the other substances mentioned in B in the same 
way. Do they act like the egg? 

D. Biuret Test, or Piotrowski's Reaction. To a little white 
of egg in water add 10 c.c. of biuret reagent. Note the color 
change." Boil the mixture. Does the color change? Note 
the result. Test the other substances mentioned in B in 
the same way. ^V<^.^M^ 

(Of the three chemical tests for protein given above, the 
xanthoproteic is best for general use. There are many 
forms of protein, but these tests will indicate its presence 
whatever its form may be.) 



STUDY OF NUTRIENTS 33 

XVII. CARBOHYDRATES STARCH 

Apparatus. Solution of iodine, l laundry starch, white of egg, 
olive oil, test tubes. 

Directions. Place a little starch in a test tube and fill 
the tube a quarter full of water. Shake it. Does the starch 
dissolve? " Prove your statement by applying one of the tests /,- 
described in Exercise V. Boil. What happens to the starch? J 

Put a little of the starch paste in a test tube with an 
inch of water. (Shake, to get thorough mixture.) Now add 
a drpp pf the solution of iodine. What co^or does the paste be- 
come?^ Heat. What becomes of the color? ^Should the iodine 
test be applied to hot or cold starch-containing substances? <*<-J? 

Test a little white of egg and olive oil (which contain no 
starch) in the same way. Do you get the same result? ^ . 

(This test will indicate the presence of starch, whatever 
may be its form.) 

XVIII. CARBOHYDRATES GRAPE SUGAR (GLUCOSE) 
AND CANE SUGAR (SUCROSE) 

Apparatus. Fehling's solution 2 or Benedict's solution, 3 glucose, 
starch, oil, test tubes, concentrated hydrochloric acid, cane sugar. 

1 To make the iodine solution, dissolve a teaspoonf ul of potassium iodide 
crystals in a tumbler of water. Add crystals of iodine and stir until a rich 
wine color is obtained. This may be bottled and used as needed. 

2 To make Fehling's solution: 

Fehling's solution is composed of two definite solutions a cupric 
sulphate solution and an alkaline tartrate solution. 

Cupric sulphate solution = 34.65 grams cupric sulphate dissolved 
in 500 c.c. of water. 

Alkaline tartrate solution = 125 grams potassium hydroxide or sodium 
hydroxide and 173 grams of Rochelle salts dissolved in 500 c.c. of water. 
Keep these solutions separate until ready for use. Prepare for test by 
mixing equal portions. 

3 Dr. S. R. Benedict has devised a substitute for Fehling's solution 



34 EXPERIMENTAL PHYSIOLOGY 

Directions. A. Dissolve a little of the glucose in water 
in a test tube. Add 5 c.c. of Benedict's solution (or Fehling's 
solution) and heat to boiling. Note any changes in color. 
When no further change in color takes place, note the final 
color. Let the solution stand and note that the colored part 
separates out as a precipitate. Test in the same way oil, 
starch and any other substance that contains no grape 
sugar. Compare results. 

(This is a universal test for grape sugar.) 

B. Test for Cane Sugar (Sucrose). To 5 c.c. of a weak 
solution of cane sugar add an equal volume of concentrated 
hydrochloric acid. Boil. A deep_red color indicates cane 
sugar. 4-v 

XIX. FATS AND OILS 

Apparatus. Flaxseed (ground), beef fat, unglazed paper, ether, 
filter paper, glass funnel, evaporating dish, chemical thermometer. 

Directions. A. Put a little beef fat in the evaporating 
dish and heat. When it begins to melt stir with the chemi- 
cal thermometer and note the temperature of the melting 
point. If the body temperature is 98 F. what does this 
experiment indicate as to the condition of fats in the body? 
Name some fats that are liquid at ordinary temperatures. 

which has the advantage of not deteriorating on long standing. It is 
prepared as follows: 

" With the aid of heat dissolve 173 grams of sodium citrate and 100 
grams of sodium carbonate in about 600 c.c. of water. Pour through 
filter paper into a glass graduate and make up to 850 c.c. with water. 
Dissolve 17.3 grams of cupric sulphate in 100 c.c. of water and make up 
to 150 c.c. with more water. Pour the carbonate-citrate solution into a 
large beaker and add the cupric-sulphate solution slowly, with constant 
stirring. The mixed solution is ready for use and does not deteriorate 
on long standing." Hawk's "Practical Physiological Chemistry," 1910. 



STUDY OF NUTRIENTS 35 

B. Place a little beef fat on the unglazed paper and 
warm. Remove and examine the paper. How does it 
show the presence of fat? ^Substitute for the beef fat a 
little ground flaxseed and repeat the above process. Does 
flaxseed act like beef fat? ^t)o starch and other substances 
which contain no fat or oil act in the same way? (The 
above is a general test for fats and oils in whatever form 
they may be.) 

C. Burn a little fat and note the odor. This odor is 
characteristic of fats. 

D. Place a little beef fat in a test tube. Add enough 
ether to cover, and shake. Describe the effect on the fat. 
Filter off the ether, by means of the funnel and filter paper, 
into the evaporating dish. Let the latter stand until the 
ether evaporates. What is left in the dish? What did the 
ether do to the fat? Treat ground flaxseed in the same 
way. Is the result the same? Treat sugar, or anything 
else that contains no fat or oil, in the same way. Is the 
result the same? (The above method enables us to extract 
fat from a substance which contains it.) 

XX. MINERAL SALTS (OPTIONAL) 

Apparatus. Platinum foil or piece of sheet iron, forceps, piece 
of meat or vegetable matter. 

Directions. Place the meat on the foil and hold the 
foil in the flame with the forceps until all the black has 
disappeared from the burning meat. The residue is min- 
eral matter. Would this test be possible if this mineral 
matter were combustible? What color is the residue? 
(This is the method for determining the presence and 
amount of mineral salts.) 



36 EXPERIMENTAL PHYSIOLOGY 

XXI. WATER (OPTIONAL) 

Apparatus. Pieces of parsnip, potato, apple, lettuce leaves, flour, 
meal, meat, test tube, balance sensitive to one gram. 

Directions. A. Heat one of the above substances in a 
dry test tube. As the tube cools after having been taken 
from the flame, examine the sides and note what you see 
on them. 

B. Weigh a portion of each of the above substances, re- 
cord the weights, and place the substances in a warm, dry 
place for a few days. Then weigh again and record as be- 
fore. Continue this until there is no further decrease in 
weight. The loss of weight represents approximately the 
water contained in the substances before it evaporated. 
From your results answer the following questions: About 
what per cent of water did each substance contain? Why 
are flour and grains in general a good food for travelers to 
carry? Why are fruits and salads good hot-weather foods? 



"*' COLLEGE 
PHARMACY 



STUDY OF FOODS 



XXII. 



NECESSITY OF FOOD 

Apparatus. Wide-mouthed bottles, corks to fit, pea or corn seed- 
lings, nutrient solution, 1 test tubes, paraffin wax, distilled water. 

Directions A. Take one of the pea or corn seedlings 
and cut off the cotyledons close to the 
stem. Pass this through a hole in one 
of the corks, and insert in a bottle, as 
shown in Fig. 11. Fill the bottle about 
three-quarters full of the nutrient so- 
lution. Prepare a second seedling in the 
same way (select one of as nearly the 
same size as possible), but substitute 
distilled water for the nutrient solution. 
Note the growth of each seedling for sev- 
eral days. Do they grow equally fast? 
What sort of food is in the nutrient 
solution? From the composition of the 
water and the mineral salts, is it pos- 
sible for the plant to get its carbon from the nutrient solu- 

1 Nutrient Solution after Sachs ('82) : 

Distilled water (H 2 0) 1000. 00 




FIG. 11. 



Potassium nitrate (KNOs) 

Sodium chloride (NaCl) 

Calcium sulphate (CaSO 4 ) 

Magnesium sulphate (MgSO 4 ) 

Calcium phosphate (CaslPO 4 L) 

Ferric chloride (FeCl 3 ) 



1.00 
0.50 
0.50 
0.50 
0.50 
0.005 



c.c. 

gram 



(Do not put the ferric chloride into the solution in the first place, but 
add a drop of it to each bottle when the seedlings are put in.) 

37 



38 



EXPEKIMENTAL, PHYSIOLOGY 



tion? (Air contains a small proportion of carbon dioxide 
[see Ex. XII] and plants secure their carbon through their 
leaves, which absorb the gas from the air.) From your obser- 
vations can a plant live indefinitely on water alone? 

B. Seal the growing seedling of A to the cork with melted 
paraffin wax, cover the upper part of the seedling with a 
test tube, and seal the edges of the tube to the cork. Does 
the plant continue to live? (Plants cannot live without 
air.) What collects on the inside of the tube? What evi- 
dence have you that a plant gives off water? 

C. Prepare a third and a fourth seedling as in A. In one 
bottle put some nutrient solution made without the potas- 
sium nitrate, and in the other the normal solution. Which 
seedling lives longest? (To support life, one food required 
by plants is some nitrogen salt like potassium nitrate.) 

D. Prepare a fifth seedling as in A, using a nutrient so- 
lution with only the ferric chloride omitted. After several 
weeks, notice the effect on the color of the plant. 

XXIII. NUTRIENTS PRESENT IN COMMON FOODS 

Apparatus. Meat, flour, milk, parsnip, lettuce, peanuts, and the 
necessary materials for the tests described in Exs. XIII to XVIII. 

Directions. Apply the tests to each substance separately 
and tabulate your results as follows: 
Substance Tested. . $ 



NAME OF TEST 


REAGENT USED 


COLOR OR 
OTHER RESULT 


NUTRIENT INDICATED 


<* H"Hv > r vrfr* IC , 




... ,.,-. 


/r 


:- 


o 


K.^,v- - 





STUDY OF FOODS 



39 



Under " Reagent " tell the chemicals used. 

Under " Color or Other Result " state exactly what 
happens. 

Under " Nutrient Indicated " write the name of nutrient 
and the word present or absent. 

XXIV. STUDY OF FOOD CHARTS 1 



FOOD 


COMPOSITION PERCKNTAGB OF NUTRIENTS 


Energy in 
Calories 
per 
Pound 


Average 
Cost 
per 
Pound 


Pro- 
tein 


Starch 


Other 
Carbo- 
hydrate 


Fat 


Water 


Min- 
eral 


Bread (White) 


8. 


47. 


3. 


1. 


37. 


2. 


1280. 


$.04 


Flour 


11. 


66. 


4.2 


2. 


15. 


1.7 


1645. 


.025 


Oatmeal 


12.6 


58. 


5.4 


5.6 


15. 


3. 


1850. 


.05 


Rice 


6. 


79. 


0.4 


0.7 


13. 


0.5 


1630. 


.07 


Beans 


23.1 


55. 


2. 


2. 


12.6 


3.1 


1615. 


.05 


Potatoes 


2. 


18. 


3. 


0.2 


76. 


0.7 


375. 


.0125 


Milk 


4. 





5. 


4. 


86. 


0.8 


325. 


.035 


Cheese 


28.3 





1.8 


35.5 


30.2 


4.2 


2070. 


.16 


Beef (Round) 


20.5 








10.1 


68.2 


1.2 


805. 


.14 


Beef (Corned Flank) 


14.2 





. 


33. 


49.8 


3. 


1655. 


.10 


Mutton (Leg) 


18.3 








19. 


61.8 


0.9 


1140. 


.18 


Veal (Shoulder) 


20.2 








9.8 


68.8 


1.2 


79.0. 


.20 


Pork (Shoulder Fresh) 


16. 


. 





32.8 


50.3 


0.9 


1680. 


.16 


Pork (Ham) 


16.7 








39.1 


41.5 


2.7 


'I960. 


.16 


Pork (Salt Fat) 


0.9 








82.8 


12.1 


4.2 


3510. 


.12 


Chicken 


24.4 








2. 


72.2 


1.4 


540. 


.20 


Eggs 


14.9 








10.5 


73.8 


0.8 


721. 


.18 


Butter 


1. 





0.5 


85. 


10.5 


0.3 


3615. 


.30 


Codfish 


15.8 








0.4 


82.6 


1.2 


310. 


.08 


Mackerel 


18.2 








7.1 


73.4 


1.3 


640. 


.12 


Oysters 


6. 





3.7 


1.2 


87.1 


2. 


230. 


.25 



DIETARY STANDARDS 



CONDITIONS 


PROTEIN 


CARBO- 
HYDRATES 


FAT 


CALORIES 


Man with light muscular exercise 
Man with moderate muscular ex- 
ercise. 


0.22 Ibs. 
0.28 Ibs. 


0.88 Ibs. 
99 Ibs. 


0.22 Ibs. 
0.28 Ibs. 


2980. 
4520 


Man with active muscular work 


0.33 Ibs. 


01. 10 Ibs. 


0.33 Ibs. 


4060. 



1 More extensive tables may be found in a pamphlet printed by the 
Department of Agriculture, Farmer's Bulletin No. 23, " Foods, Nutritive 
Value and Cost," by W. O. Atwater. See also Bulletin No. 13, Series I, 
March, 1909, of the American School of Home Economics. 



40 EXPERIMENTAL PHYSIOLOGY 

Questions to be answered from study of Food Chart. 

Fat and carbohydrates are the energy producers: how 
does the table show this? What sorts of foods are richest 
as protein furnishers (tissue builders)? Of the animal and 
vegetable foods, which are richest in protein? fat? carbo- 
hydrates? 

Calculate the cost, amount of energy in calories, and per 
cent of nutrients, in the following daily dietaries: 

(a) 13 ounces of beef (round), 3 ounces of butter, 6 ounces 
of potatoes, 22 ounces of bread. 

(6) 4 ounces of salt pork, 2 ounces of butter, 16 ounces 
of beans, 8 ounces of bread. 

(c) 10 ounces of beef (corned), 1 ounce of butter, 16 ounces 
of milk (pint). 

Make up a suitable daily dietary for each of the three 
different classes of men given in the table. 



HISTOLOGICAL STUDIES 



XXV. PARTS OF A CELL 

Apparatus. Scalpel, compound microscope l with two-thirds and 
one-sixth inch objectives and one inch ocular, glass slides and cover 
glasses, pieces of filter paper, methyl green or Delafield's ha3ma- 
toxylin. 2 

Directions. Sterilize the scalpel by holding it in boiling 
water, then scrape the inside of the cheek lightly with the 




Fia. 12. A, diagram of a cell; w, cell wall with enclosed cytoplasm; n, nucleus, 
consisting of nuclear membrane inclosing granular substance, in which are seen a 
spherical nucleolus and irregular masses of chromatin; a, centrosome; B-F, changes 
that take place during cell division. 

blade. When the scalpel is removed from the mouth there 
will appear on it the scrapings in the form of a white sedi- 
ment. Remove a little of this sediment and mount in a 

1 Bausch & Lomb and the Spencer Lens Company furnish at request 
a pamphlet describing all the parts of the microscope and the method 
of handling the instrument. 

2 For the preparation of these stains consult any manual of microscopy. 
Lee's "Vade Mecum" or Guyer's "Animal Micrology"is recommended. 

41 



42 EXPERIMENTAL PHYSIOLOGY 

drop of water on the slide. Cover with the cover slip and 
examine with the two-thirds objective (low power). In 
focusing, the best results are obtained if nearly all the light 
is excluded by the diaphragm. 

Draw what you see. Note that the masses are made up 
of separate elements (cells). Compare with Fig. 12, A. 
Are the walls circular, as in the figure? 

Place a drop of the methyl green at one side of the cover 
slip and by placing the filter paper at the opposite side draw 
this solution under the slip. Let the slide stand for a mo- 
ment and examine again with the low power. What part 
of the cell has changed color? (This part is called the nu- 
cleus of the cell.) 

Now focus on one of these cells with the one-sixth ob- 
jective (high power). Has the cell a definite outline? Note 
the clear liquid between the nucleus and the outline. Do 
you notice any particles floating in this liquid? Draw this 
cell, magnified to an inch diameter, and label as follows: the 
outside boundary or cell wall; the clear liquid or protoplasm; 
the particles floating in this protoplasm, or granules; the 
nucleus. 

XXVI. STUDY OF A PLANT CELL 

Apparatus. Pond scum (Spirogyra), physiological salt solution, 1 
materials described in Ex. XXV. 

Directions. Mount a little of the pond scum in a drop 
of water and cover with a glass. Examine with the low 
power. Do you see any separate units in this case? How 
are they arranged? What is their color? Is this color 
evenly distributed throughout the cell or located in definite 

1 Physiological salt solution is made by adding 6 grams of common 
salt (NaCl) to 1 liter (1000 c.c.) of distilled water. 



HISTOLOGICAL STUDIES 43 

parts of the cell? Can you see any cell wall? protoplasm? 
nucleus? Make a drawing of what you see and label in such 
a way as to answer the above questions. 

Now add a little of the physiological salt solution, to be run 
under the cover glass, and examine with the high power. Do 
you see any nucleus now? any protoplasm? What has hap- 
pened to the protoplasm? Draw and label such parts of 
the cell as show. A little methyl green or Delafield's hsema- 
toxylin added will make the nucleus more distinct. 

Make a list of the differences and similarities between the 
cells examined in Ex. XXV and Ex. XXVI. 

NOTE. The comparison of cells should be further demonstrated 
with other materials by the instructor, until the essential and varia- 
ble components are clearly grasped by the pupil. Some suggested 
material: Pleurococcus, potato, diatoms, root tips, etc. 

XXVII. STUDY OF LIVING PROTOPLASM AMOEBA 

Apparatus. About a month beforehand collect the leaves and 
sediment from pools of still but clear water. Distribute this mate- 
rial together with a few water plants (Nitella or Chara) in sev- 
eral open, shallow dishes. Keep covered with water. When, in 
course of time, the water in these has become clear and free from 
scum, take up with a pipette (medicine dropper) some of the sedi- 
ment from the very surface of the leaves. Examine this for amoebae 
with the low power (two-thirds objective). When the dish contain- 
ing them in quantity is located, mark this for supply. 1 The other 
apparatus is the same as in Ex. XXV. 

1 A. W. Weysse of Boston University gives in " Science," Vol. XX, No. 
515, the following method of securing amoeba. Collect a considerable 
number of lily pads. Remove with a spatula the slime which adheres to 
the lower surface and put it in a shallow glass aquarium containing water 
six or eight centimeters deep. Place the vessel near a window, and in a 
week or two amoebae will be abundant on the surface of the sediment at 
the bottom. 



44 EXPERIMENTAL PHYSIOLOGY 

Directions. Mount some of the amoebae on a glass slide 
and cover them with a cover slip. Locate one of the animals 
with the low power and then focus on it with the high power 
for careful observation. 

Watch the amoeba until it begins to show movement, then 
draw and note the following parts: round, opaque nucleus, 
the clear outer part (ectoplasm) and the granular inner part 
(endoplasm) of the cytoplasm. (Cytoplasm is the name given 
to that part of the protoplasm which is not nuclear, since 
the nucleus is also composed of protoplasm.) Note, further, 
the round spots in the cytoplasm (vacuoles: food vacuoles, 
water vacuoles, or contractile vacuoles, according to con- 
tents); the constantly forming projections of the cytoplasm 
(pseudopodia) ; and the absence of any cell wall. 

(Amoeba is a one-celled animal made up of free protoplasm, 
and hence well suited to show the properties of this sub- 
stance, which is the physical basis of all life.) 

Properties of Protoplasm 

A. What color is the cytoplasm? Does it appear thicker 
or thinner than the water? Is the part containing granules 
of the same color as the clear part? Does this cytoplasm 
mix with the water? Describe the appearance of the 
nucleus. 

B. Movement. Watch the moving amoeba. Note the va- 
rious steps in the forming of a pseudopodium. Is the move- 
ment of the animal rapid? Does it appear to move in a 
definite direction or at random? Do the particles in the 
water appear to affect its movement? Press on the cover 
glass with a needle point just above the amoeba. How does 
the amoeba react? Note that the movement of the amoeba 
is produced as a result of two properties of protoplasm, 



HISTOLOGICAL STUDIES 



contraction and expansion. A substance showing these 

properties when it is stimulated is said to have contractility. 

C. In B we noted that the animal contracted and ex- 




FIG. 13. A, Amoeba proteus: a, food vacuole; c, contractile vacuole; ec, ectoplasm; 
en, endoplasm; n, nucleus; v, water vacuoles. B, Amoeba radiosa. 

panded without apparent cause in some cases. We noted 
also that under pressure it contracted more strongly. This 
power to respond to special stimuli is called irritability. 
Test the irritability of the protoplasm toward heat by ap- 
plying the flame of an alcohol lamp gently to the end of 



46 EXPERIMENTAL PHYSIOLOGY 

the glass side. Record your observations as the heat grad- 
ually increases. Other tests may be made by running solu- 
tions of various salts, etc., under the slide. 

D. Feeding Habits. Examine the contents of some of the 
vacuoles and state your conclusions as to the form of food 
taken in by the protoplasm. Note and describe the method 
of engulfing these food particles and the forming of the 
vacuole. Compare several. of these vacuoles as to the con- 
dition of their contents. From these observations, what do 
you conclude happens to food in the amoeba? 

(The process of taking in food is called ingestion. The 
process of dissolving ingested food is called digestion. The 
process of transforming digested food into protoplasm is 
called assimilation. This last process is evidenced by the 
decreasing size of the vacuole after the food is dissolved.) 

E. The Removal of Wastes. Study the action of the large 
contractile vacuole. What does it appear to contain when 
expanded? Where does this substance come from? Where 
does it go when the vacuole is contracted? Does the vacuole 
pulsate regularly? 

(The process of collecting the broken-down waste of the 
body and its removal to the outside is called excretion. 
The processes described in D, by means of which pro- 
toplasm is made, are spoken of collectively as anabolism. 
The processes by means of which old protoplasm is broken 
down and removed are spoken of collectively as katabolism. 
Metabolism is the simultaneous occurrence of these two ac- 
tions in a living body of protoplasm.) 

F. Place several amoebae in a drop of water in a vial and 
cork the vial tightly. The water used should be rich in 
food bacteria. Also, for comparison, make a balance prep- 
aration consisting of the same number of amoebae mounted 



eer 



in the same amount of water in a watch glass, this prepara- 
tion to be exposed to the air in a large vessel containing a 
little water to prevent evaporation. Examine at the end 
of a few days. What evidence have you that protoplasm 
requires air? 

(It is the oxygen in the air that the animal uses. This 
property of taking in air and oxygen is part of a process 
called respiration.) 

Make a list of all the properties of protoplasm as exhib- 
ited by the cytoplasm of the amoeba. 

XXVIIL EPITHELIAL TISSUE (OPTIONAL) 

Apparatus. Prepared slide 1 of cross section of the small intes- 
tine (human preferred, but rat's or other mammars will serve), com- 
pound microscope. 





FIQ. 14. FIG. 15. 

Epithelial Tissues, a, two forms of epithelial tissue: 1, columnar; 2 and 3, squamous; 
c, stratified tissue; 6, simple ciliated tissue; d, ciliated columnar tissue. 

Directions. Focus with the high power on the cells 
forming the inner layer of the intestine. Draw six or eight 

1 Prepared slides for study of tissues may be bought best of dealers, as 
their preparation is a matter of delicacy and skill. For those who wish to 
prepare their own, suitable directions will be found in standard histologies, 
such as Stohr's or Schafer's, and in Lee's " Vade Mecum " or Guyer's 
"Animal Micrology." 



48 



EXPERIMENTAL PHYSIOLOGY 



of these cells, showing the large nucleus in each, the general 
outline of the cells, and the distribution of the protoplasm. 
Note the thinness of the cell wall and the absence of inter- 
cellular material. Compare these cells (columnar epithelium; 
see Fig. 15, d) with those of Ex. XXV (squamous epithelium; 
see Fig. 14, a, 2 and 3, and c). How do they differ? Note 
the protective character of these layers of cells with reference 
to the underlying layers. (One feature of this protection is 
prevention of the action of digestive fluids upon the under- 
lying muscles and other forms of tissue.) 

XXIX. CONNECTIVE TISSUE (OPTIONAL) 

Apparatus. Prepared slides of intermuscular tissue, cartilage, 
and bone, compound microscope. 

Directions. A. Intermuscular Tissue. Draw, under the 
low power. Note two classes of bundles of fibers (white 

fibers and elastic). The elastic 
fibers are single and are more 
sharp in outline than the white. 
Find one of the cells (or corpus- 
cles) and focus with the high 
power. Draw it, and show in your 
drawing its relation to the two 
classes of fibers. From your 
study, which part of this tissue . 
should you say was most impor- 
tant, the cellular part or the in- 
tercellular fibers? 

B. Cartilage (hyaline). Note 
the solid character of the inter- 
cellular matrix, the outlines of the cells with their proto- 
plasm and 'nucleus, the lacunce, or pits in which the cells 




Bundle of White Fibers 
FIG. 16. Intermusoular Tissue. 



HISTOLOGICAL STUDIES 



49 






lie, and the capsules inclosing these lacunae. Which part of 
this tissue is supporting, the cells or the matrix? Draw 
a section, under the high 
power, and label all parts. 

C. Bone. Note the ma- 
trix of spongy bone arranged 
in concentric rings (lamellae) 
around the central canals 
( Haversian canals) . Between 
the lamellae note the irregu- 
lar cavities lacunce) with 
their wavy branches or cana- 
liculi. Note how these ca- 
naliculi connect the lacunae 
with one another and with 
the Haversian canals. Look in the lacunae for the bone cells. 



cop. 



Fio. 17. Hyaline Cartilage: cap, capsule; 
m, matrix formed by cells; c, cartilage 
cell; n, nucleus. 




Fia. 18. Bone: a, canaliculi; b, Haversian canal; c, lacuna. 

(In ground sections of bone these will probably be wanting. 
They appear better hi sections of decalcified bone.) Draw, 



50 



EXPERIMENTAL PHYSIOLOGY 



under high power, a section locating all the above-named 
parts. 

(Note in the three classes of connective tissue that the 
intercellular portion is the important part in support. The 
importance of the cells becomes clear when it is understood 
that this intercellular matrix is produced by them.) 

XXX. MUSCULAR TISSUE (OPTIONAL) 

Apparatus. Prepared slides of striated and non-striated muscle, 
compound microscope. 

Directions. A. Non-striated. Note the long, spindle- 
shaped cells, the elongated nucleus, and the homogeneous 

protoplasm filling the whole 
cell. Note, further, how these 
FIQ. 19. A Non-striated Muscle Ceil; n, cells interlace. (They are held 

together by a homogeneous 

cement substance.) Note the absence of any striation, or 
striping. Draw several of these cells under the high power, 
locating all the parts mentioned above. 

B. Striated. Examine a single fiber with the high power. 
Note the broad, dim, transverse striae and 
the narrow, light, transverse striae. The 
broad stria is called anisotropic or doubly 
refracting, contractile sarcoplasm. The nar- 
row stria is called isotropic or singly refract- 
ing sarcoplasm. Note also the more or less 
dim longitudinal striation. Over the whole 

FIG. 20. Portions of 

of the fiber is stretched the transparent striated Muscle 
sarcolemma, or cell wall. Somewhere on Fibers. (The figure 

shows the striae 

the fiber may be found also several nuclei. and the nuclei. ) 
Draw and locate all these parts of the muscle cell. (Sar- 
coplasm is merely another name for the protoplasm of a 
muscle cell.) 




v 



HISTOLOGICAL STUDIES 



XXXI. NERVOUS TISSUE (OPTIONAL) 



51 




Dendrites 



Nerve process 



Axis cylinder 



Neurilemma 



Apparatus. Prepared slides of ganglion cells and nerve fibers, 1 
compound microscope. 

Directions. A. The Nerve . 
Cell. Note the irregular outline y 
of the cell; the wavy projec- 
tions, or dendrites; the rodlike 
projections, or nerve processes. 
Note the position of the nu- 
cleus. Has the cell one or 
more nerve processes? Draw 
and locate all parts, under the 
high power. 

B. The Nerve Fiber. Make 
out from your study of the 
nerve fiber the axis cylinder 
in the center. (This corre- 
sponds to the nerve process of 
A.) Next outside this is the 
medullary sheath, and on the 
very outside the neurilemma. 
Make a drawing showing all 
these parts. For their relation 
compare with Fig. 21. 

All tissues of the body can 
be placed in one of the above 
classes, epithelial, connective, 
muscular, or nervous. 

1 A smear preparation of spinal cord may be prepared as follows : Rub a 
piece of fresh spinal cord in water between two cover glasses. Mount and 
run under the cover glass a drop of methyl green. Both nerve fibers and 
nerve cells appear in such a preparation. 




Terminal 
branches 



FIG. 21. Scheme of a Neuron: a, 
free axis cylinder; 6, axis cylinder 
surrounded by neurilemma alone; 
c, axis cylinder surrounded by 
medullary sheath alone; d, axis 
cylinder surrounded by the sheath 
and neurilemma and divided into 
segments (by constrictions called 
the nodes of Ranvier). 



PRINCIPLES OF DIGESTION 



XXXII. PRINCIPLES OF OSMOSIS. 



Apparatus. Potassium bichromate, glucose, white of egg, starch, 
beet root, Fehling's solution, iodine solution, Millon's reagent, dialyzer. 
There are several forms of dialyzer described by different authors, 
any one of which will serve. (1) The following form has been 

found very satisfactory : Take ordinary 
collodion and a glass beaker. Pour the 
collodion into the beaker and then pour 
out again, revolving the beaker so as to 
bring the collodion into contact with 
the entire inner surface of the glass. 
Let the beaker drain for a few mo- 
ments. The ether will evaporate and 
leave a thin skin on the inside of the 
beaker. As soon as the skin is tough 
enough, loosen it at the top and pour 
water between it and the glass. With 
care the entire skin will separate from 
the glass, giving a membranous bag 
which is exactly the shape of the beaker, 
is water tight and ideal for these ex- 
periments. Any shape bag may be 
obtained by selection of the receptacle. 
(2) Obtain from the butcher some skins 
such as are used to hold sausage meat. 
Tie one of these around the base of a 
student lamp chimney, as in Fig. 22, after cutting off the chimney so 
that it is only about six inches in height. Select a cork to fit 
tightly in the top of the chimney and, with a cork borer, puncture 
this to fit an eighth-inch glass tube about a foot in length. Arrange 
the whole apparatus as in the diagram, supporting the chimney in 
an outer jar so that it will not rest on the bottom. To fill the 

52 




FIG. 22. 



PRINCIPLES OF DIGESTION 



53 



chimney, remove the cork and tube. The tube will serve as a deli- 
cate indicator of the amount of rise in the water. 

Directions. A. Put into the dialyzer some crystals of 
potassium bichromate. Fill with water both the dialyzer 
and the outer jar until the level is the same in each. Allow 
them to stand for a short time. Then examine and note the 
level of water in the two parts. What has been the pre- 
vailing direction of flow of water? Is the color of the water 
in the outer jar changed? Has some of the salt solution in 
the dialyzer passed through the membrane? (This inter- 
change of water and salt solution through a membrane 
the sausage skin or the collodion is called osmosis.) 

B. Place some glucose in a beaker with some water. 
When the grape sugar is well dissolved, transfer this liquid 
to the dialyzer. Fill both dialyzer and outer jar to the same 
level with water as before. Note the direction of the water- 
flow. Test the water in the 

outer jar with Fehling's 
solution. What results? 
Does grape sugar in solu- 
tion pass readily through 
the membrane? (Sub- 
stances which pass readily 
in solution through a 
membrane under the FlQ . 23 ._^ living cell; Bt cell whoge proto . 

above Conditions may be plasm has been killed by boiling; cw, cell 
. -, , N wall; n, nucleus; p, protoplasm. 

said to osmose.) 

C. Substitute for the glucose solution" a diluted starch 
paste. After a time note the level of the water. Record 
its direction of flow. Test the liquid in the outer jar with 
iodine solution. Does starch osmose? Does starch crystal- 
lize like grape sugar and potassium bichromate? 




54 EXPERIMENTAL PHYSIOLOGY 

D. Substitute for the starch paste a solution made of 
white of egg whipped up in water. Note direction of flow 
of water. Test the water in the outer jar with Millon's 
test for proteid. Does egg albumin osmose? 

E. Cut a few slices of beet root. Wash, and place a few 
pieces in two separate beakers. Fill each beaker half full 
of distilled water. Boil the slices in one of the beakers. 
(This kills the protoplasm in the cells of the beets without 
injury to the cell walls.) Add a few drops of hydrochloric 
acid to each beaker, and then test with Fehling's solution 
for grape sugar. In which has the sugar dialyzed from the 
cells? In which is the water colored? Study tne arrange- 
ment of protoplasm in a dead and in a living cell, as 
illustrated in Fig. 23, and state your conclusions as to the 
influence of protoplasm on osmosis. 

(Substances that osmose are called crystalloids. Sub- 
stances that do not osmose are called colloids.) 

F. Make a mixture of grape sugar, white of egg, and 
water. Put in the dialyzer with water on the outside. 
After a time test the water with: (a) Benedict's or Feh- 
ling's solution. Result? (6) Biuret reagent. Result? Sep- 
aration of crystalloids from colloids by osmosis is called 
dialysis. 



f 



'(flP 



XXXIII. AN ENZYME 



Apparatus. Ground malt, starch, test tubes, iodine solution, 
Fehling's solution. 

Directions. Make an extract of malt diastase (an en- 
zyme) by shaking up five grams of ground malt with 50 c.o. 
of cold water. Let it stand for a few hours and then filter. 
Make a thin starch paste by mixing a teaspoonful of starch 



PRINCIPLES OF DIGESTION 55 

with a cup of boiling water. 1 Fill two test tubes half full 
of this starch preparation. Test a little of the starch prep- 
aration with the iodine solution, to determine strength of 
reaction. Test a little of the starch preparation, and also 
some of the diastase solution, with Fehling's solution. Is 
grape sugar present in either of them? Now add 10 c.c. 
of diastase solution to one of the test tubes; warm both 
tubes, and keep them as near as possible at a constant 
temperature of 45 C. 

At intervals of five minutes remove a little of the con- 
tents of each tube with a pipette and test with the iodine 
solution. Do the same-, using Fehling's solution instead of 
iodine solution. Is the amount of starch on the increase or 
the decrease in either tube? After how long a time do you 
get a test for grape sugar, and in which tube? Continue 
these tests until you get a strong test for grape sugar. 

(The reason for these results is that the malt diastase 
the enzyme is slowly changing the starch into sugar. An 
enzyme is a substance which can bring about the trans- 
formation of one chemical compound, such as starch, into 
another, such as sugar, without itself being used up. The 
value of enzyme action in our bodies lies in the fact that 
by it a colloid, like starch, may be changed into a crystalloid, 
like sugar, which can then be absorbed through a membrane 
by osmosis, e.g., from the stomach through the walls of the 
blood vessels into the blood.) 

1 To make clear starch paste, free of lumps, first have the water 
boiling vigorously. Then mix the starch with a little cold water, 
shaking to get a milky fluid. Now add the milky fluid, a drop at a 
time, to the boiling water. Stir constantly while adding the starch. 
This paste may be kept for a considerable time by adding a little pow- 
dered thymol. 




EXPERIMENTAL PHYSIOLOGY 

XXXIV. A FERMENT ORGANISM YEAST . 

Apparatus. Yeast cake, molasses, eight-ounce bottle, absorbent 
cotton, limewater, chemical thermometer. . 

Directions. Dissolve a piece of yeast cake, the size of 
a pea, in two tablespoonfuls of water. Pour this into the 
eight-ounce bottle. Add to this a tablespoonful of mo- 
lasses and fill the bottle half full of water. Stopper with 
a plug of absorbent cotton and leave in a warm place for 
twenty-four hours. Record the temperature of the room /V 
in which the bottle is put and the temperature of the 
mixture, ty* 

At the end of the twenty-four hours remove the stopper 
and examine the contents. What is the temperature? 
Does it smell sweet? Test the gas in the top of the bottle 
with a drop of limewater. What gas gives this reaction?3?v 
Does the odor give you any evidence of the presence of 
alcohol? Examine under the low power of the compound 
microscope a little of the sediment from the bottom of the 
bottle, mounted in water. Draw several 
groups of the separate elements of this 
sediment. (These bodies are yeast plants.) 
(Yeast is a one-celled plant that, with- 
out changing its yeast character, is capable 
of transforming sugar into carbon dioxide 
and alcohol. In its power to change a 

Flo 24. Yeast Plants: substance, without itself undergoing trans- 

i, a plant forming a formation, it acts like an enzyme, and 

bud; 2, the bud near- 
ly ready to separate hence is called a ferment organism. The 

as a new plant. yeast cell in growing actually secretes an 

enzyme which produces this change. Hence a " ferment or- 
ganism " is simply a cell or collection of cells which secrete 




PRINCIPLES OF DIGESTION 



57 



enzymes. Many digestive actions are performed by en- 
zymes. Most enzymes are produced in the body by the 
cells of organs called glands.) 




<XXXV. STRUCTURE OF A TYPICAL GLAND. 

Apparatus. Microscope and accessories used in the study of 
tissues, prepared slide of crypt of Lieberkuhn from the small intestine 
of man. (Any other gland preparation will serve.) 

Directions. Examine first with the low power. Draw 
the entire gland and note the following points: the kind of 
tissue, the arrangement of the cells, the gland lumen, or 




FIG. 25. A Salivary Gland; a, lumen 
of a gland in longitudinal section; b, a 
gland in cross section; c, connective 
tissue. 




Fia. 26. Forms of Glands. 



central cavity. With the high power examine a few of the 
cells and their contents. Draw, and note the position of 
the nucleus, the protoplasm, and the secretion in various 
cells. Fig. 26 illustrates the relation of the simple, tubular 
gland, such as you have just studied, to the compound forms. 



ORGANS AND PROCESSES OF DIGESTION 



XXXVI. DISSECTION OF A RAT'S DIGESTIVE ORGANS 

Apparatus. Rat, 1 dissecting tray with wax lining, scissors, for- 
ceps, bristle probes, 10 % alcohol or 1 % formalin. 

Directions. Lay the rat on its back in the tray, stretch, 
and tie or pin the legs as in the diagram. Cover with 10 % 

alcohol or 1 % formalin. 

Locate the lower end of 
the breast bone and slit the 
skin from this point to the 
anus. On each side, at the 
middle point of the slit, 
make a slit at right angles. 
Turn back the four flaps 
and pin them. 

Note the thin membrane 
(peritoneum) lining the ab- 
domen. Is it flexible? Re- 
move this and, without dis- 
t u r b i n g the underlying 
FIG. 27. parts, locate the stomach, 

the liver, and the coiled intestine. 

Press the intestine downward and determine the size, 
position, shape, and color of the stomach. Find the ends 

1 This exercise may be made a demonstration. In that case a larger 
animal, such as the rabbit, would be preferable. 

58 





ORGANS AND PROCESSES OF DIGESTION 59 

that are connected with the intestine (pyloric end) and with 
the esophagus, or gullet (cardiac end). Note the covering 
of blood vessels. 

In the fold of the intestine (duodenum) next to the stom- 
ach, locate the fatty-looking pancreas, f Find its duct and 
trace its connection with the duodenum. 

Press forward the liver and, on its posterior surface, find 
bile sac. Locate the connection of this with the two 
lobes of the liver (the hepatic ducts). Open this sac and, 
with the probe, find its connection (the bile duct) with the 
pancreatic duct and the duodenum. Note that the bile duct 
and the pancreatic duct fuse and enter the duodenum by a 
common duct. 

-Examine the membrane (mesentery) which supports the 
intestine. Note its blood vessels. Carefully unravel the in- 
testine (Caution! do not break it) from the stomach to the 
anus. Determine the relative lengths of the small and the 
large intestine and the method of their joining. (This con- 
nection is guarded by a valve which acts in such a way as 
to prevent matter returning from the large to the small 
intestine.) 

--Slit the stomach just below the gullet entrance and, 
with the probe, find its connection with the mouth. Above 
the liver and the stomach, find the muscular partition 
(diaphragm) separating the abdominal from the thoracic 
cavity. 

Illustrate, by a diagrammatic drawing, the connections 
of the following parts: mouth, gullet, stomach, liver, pan- 
creas, small intestine, large intestine. 

Carefully remove the stomach, liver, pancreas, and intes- 
tines, and preserve the rest of the animal for further dis- 
section in 85 % alcohol or 4 % formalin. 




x 



EXPERIMENTAL PHYSIOLOGY 

XXXVII. THE TEETH 

Apparatus. A hand mirror, a molar tooth sawed in vertical sec- 
tions, an apple. 

Directions. A. Kinds of Teeth. With the aid of the 
mirror and the finger count the number of teeth on each jaw. 
Is the number the same? Note that they may be divided 




a 








FIG. 28. a, incisors; 6, canines; c, premolars; d, molars. 

into four classes according to shape. How many broad 
teeth (incisors) have you in the front of each jaw? How 
many with one point on the surface (canines)! How many 
with two surface points (bicuspids or premolars)! with more 
than two surface points (molars)! Tabulate these numbers 
as follows: 





UPPER JAW 


LOWER JAW 


Incisors 






Canines 






Premolars 






Molars 







Grand Total 



PRINCIPLES OF DIGESTION 



61 



Examine the mouths of animals, such as the squirrel or 
rat, the cat or dog, and the horse or cow. How do they 
differ as to the kind and number of their teeth? What kind 
of food does each animal eat? Which kind of food requires 
the most chewing? Do you see any connection between 
the food and the kind of teeth which predominates in each 
animal? 

B. Structure of a Tooth. Draw a section of a molar tooth. 
Find the following parts: the crown, the neck, roots or fangs, 
the covering of the crown (enamel), 

the covering of the fangs (cement), 
the central or pulp cavity with nerve 
and blood-vessel aperture, the mid- 
dle layer (dentine). Label all these 
parts in your drawing. Examine, if 
possible, the jaw of a human skele- 
ton to show the insertion of the teeth 
in it. 

C. The Use of the Teeth. Bite off 
a piece of apple and chew it. An- 
swer the following questions: Which 
teeth are used in the biting off of the 

apple? which to chew it into small pieces? How are these 
latter best adapted to break up the food? Of what advan- 
tage is it that a horse's molars are ridged on the surface? 
Could you tell from the examination of the teeth the kind of 
food an animal eats? 

When a tooth decays what part actually decays? What 
is the difference in the functions of the enamel and of the 
dentine? How does the location of the nerves in the pulp 
cavity protect them? Why is a decayed tooth apt to 
ache? 




FIG. 29. -A Molar: k, crown; 
n, neck; /, fangs; e, enamel; 
d, dentine enclosing the pulp 
cavity; c, cement. 



62 >0f EXPERIMENTAL PHYSIOLOGY 

[VIII. PREPARATION OF DIGESTION FLUIDS 
(OPTIONAL) 

A. Collection of Saliva. With aid of a piece of paraffin 
to chew, stimulate the flow of saliva and collect in a small 
beaker as fast as it forms. Filter this through a wetted 
filter paper and use the filtrate. The saliva should give 
no test with Fehling's or Benedict's solution. 

B. Artificial Gastric Juice. Obtain a pig's stomach. Cut 
it open and wash its contents out by gently flushing it with 
water. Remove the mucous membrane from the cardiac 
end, and after drying this with filter paper mince it and 
bottle with four or five ounces of glycerine. (The glycerine 
dissolves the pepsinogen.) After three days filter through 
muslin. The filtered solution may be kept indefinitely. 
When required for use add 0.2 % hydrochloric acid in the 
ratio of 10 parts of the acid to 1 part of glycerine solution. 
This acid converts the pepsinogen to pepsin. 1 

A substitute for the above is solid pepsin powder dis- 
solved in water. For use, this should be treated with 0.2 % 
hydrochloric acid in the same way as the glycerine solution. 

C. Artificial Pancreatic Juice. Obtain sheep pancreas. 
Remove all lumps of fat and mince the pancreas thoroughly. 
Next grind the minced mass with a little sand and water in 
a mortar, until it is in the form of a thin paste. Pour this 
paste into a bottle and add 150 c.c. of 30 % alcohol. Shake 
repeatedly and let stand for 24 hours. At the end of that 
time strain the extract through cheesecloth and then filter 
through wet filter papers. For use add to 1 volume of the 
alcohol extract 2 volumes of 0.5 % sodium carbonate solution. 

1 If required for use at once, the membrane may be extracted with 
0.2 % HC1 directly, without the use of the glycerine. 



63 

A substitute for this solution may be made by dissolving 
the solid pancreatin powder in water. For fat digestion add 
to this the sodium carbonate solution in the same way as 
to the pancreas solution. 

D. Bile. Open and extract the contents of an ox gall 
or dissolve prepared ox gall in water. 

E. Temperature Conditions. To obtain the best results in 
all artificial digestion experiments keep the materials used as 
nearly as possible at a constant temperature. For this pur- 
pose it is suggested that a constant-temperature water bath 
be used, if possible. If this is unavailable, an ordinary dry- 
ing oven may be used with an Argand burner. Another 
substitute is a deep agate dish, such as is used in 
cookery, with the Argand burner. Place in test tubes 
the fluids and materials to be digested. Cover the top 
of the agate dish with a wooden cover having holes bored 
to fit the test tubes, and suspend the tubes in these. 
Fill the dish half full of water and heat it to the tem- 
perature desired. Adjust the Argand burner to maintain 
just that temperature. 



XXXIX. SALIVARY DIGESTION 

Apparatus. A little salt, dry cracker, dilute starch paste, white 
of egg, olive oil, saliva, litmus paper, Fehling's solution, concen- 
trated hydrochloric acid, test tubes, constant-temperature apparatus, 
dialyzer. 

Directions. A. General Functions of Saliva. Clear the 
mouth of saliva by swallowing, and wipe dry the top of the 
tongue. Place on the tongue a bit of salt. Can you taste 
the salt? Close the mouth, letting the salt stay on the 
tongue. What happens in the mouth? Where does the 



64 EXPERIMENTAL PHYSIOLOGY 

saliva come from in the mouth? Where is it made? Was 
the presence of the salt on the tongue sufficient to cause its 
flow? What does it do to the salt? Can you taste the salt 
now? Do you think the effect would be the same if the 
salt had been dissolved in water? Verify by placing a 
drop of salt water on the dry tongue. Name two functions 
of saliva that this experiment shows. 

Again clear the mouth of saliva, wipe the tongue dry, and 
place on it some powdered cracker. Try to swallow the 
cracker. Is it easily done? With the tongue moisten the 
cracker with saliva and try to swallow. Is swallowing easy 
now? What is another function of saliva? 

Chew some of the cracker slowly and note if any change 
takes place in its taste. Place on the dry tongue some 
cracker moistened with water. Is the taste the same? 
What power has the saliva that is not due to its liquid 
quality only? (This last power of the saliva is called its 
chemical power as distinguished from its purely mechani- 
cal properties.) 

B. Enzyme Action of Saliva. Collect and filter saliva as 
described in A of Ex XXXVIII. Prepare a little thin 
starch paste. Test a sample of the saliva and the starch 
paste with Benedict's or Fehling's solution. If no grape 
sugar is indicated they are ready for use. Next add 1 c.c. 
of saliva to 5 c.c. starch paste in a test tube and put in a 
water bath at a temperature of 36 Centigrade. At inter- 
vals of 10 minutes test the mixture with Benedict's or Feh- 
ling's solution. Results? What has the saliva done to the 
starch? What caused the change in taste of the cracker 
in the mouth? 

C. Conditions Affecting Salivary Digestion. Place in each 
of four test tubes 5 c.c. thin starch paste. Add a cubic 



PRINCIPLES OF DIGESTION 65 

centimeter of clear saliva to each, and label them Tubes 1, 
2, 3, 4. Pack Tube 2 in ice, boil the contents of Tube 3. 
Add a few drops of concentrated hydrochloric acid to the 
fourth tube. In a fifth tube place 1 c.c. of saliva and a little 
minced white of egg, and label it " Tube 5." In a sixth 
tube place 1 c.c. of saliva and a few drops of olive oil. 
Label it " Tube 6." Shake each tube. ^LJ*y*>^^ 
| Tube 1. Test the mixture with litmtis paper. Is it acid 
r pr alkaline? Now heat it gently to a temperature of 36 C. < , 
/Keep it at this temperature for twenty minutes and then 
test with Fehling's solution. What has the saliva done to 
tiie starch? t ^ -*r *s*y- 

Tube 2. After the second tube has been in ice twenty ^s 

inutes, test with Fehling's solution. What is the effect of fl* \ 
old on the action of saliva? 

Tube 3. Keep the third tube at room temperature ,& \ 
( twenty minutes and test as above. Note result. Let stand .*\ 
,wenty minutes longer at 36 C. and then test again with 
'ehling's solution. Result? What has the boiling done to 
the saliva? ^ ) 

Tube 4. Heat the fourth tube to 36 C. for twenty min-^/A 
f } utes and then test as above. Does the Fehling's solution * ' 
;ie any test for sugar? Reason? ^\ 

Tube 5. Heat the fifth tube to 36 C. for twenty minutes ' ^ I 
and then test with Fehling ; s solution. Does saliva convert ' 
white of egg to sugar? 

Tube 6. Treat Tube 6 in the same way as Tube 5. Does 
saliva change olive oil to sugar? 

Tabulate conditions favorable and unfavorable to salivary 
digestion. 

D. Relation of Salivary Digestion to Osmosis. In each of 
two dialyzers place 20 c.c. thin starch paste. To one add 







66 EXPERIMENTAL PHYSIOLOGY 

2 c.c. saliva. Surround each dialyzer with water, and at 
the end of 24 hours test the water with Fehling's or Bene- 
dict's solution, and with iodine solution. Does starch 
osmose? Does grape sugar? What advantage results to 
the body from the salivary digestion of starch? 



XL. PEPTIC DIGESTION 

Apparatus. Glycerine solution of pepsin or solid pepsin dis- 
solved in water, 0.2 % hydrochloric acid, concentrated hydrochloric 
acid, caustic soda, alcohol, minced white of egg, starch, beef fat, 
milk, test tubes, constant-temperature apparatus, biuret reagent, 
Millon's reagent. 

Directions. A. Action of Artificial Gastric Juice on a 
Protein. To a small piece of white of egg in a test tube add 
10 c.c. of artificial gastric juice prepared as described in 
Ex. XXXVIII, B. Place in a temperature of 36 C. and 
examine at intervals of 10 minutes. Describe the changes 
you observe. Test the final product with biuret reagent. 
Is it protein?^Boil it. Does it coagulate? State in your 
own words what the gastric juice has done to the white of 
egg. 

B. Conditions affecting Gastric Digestion. Label seven test 
tubes, Tube 1, Tube 2, etc., and prepare them as follows: 
In the first tube place 5 c.c. of the glycerine solution or v%r 
dissolved pepsin and dilute with 10' c.c. of water*;- In the 
second put 15 c.c. of the 0.2% hydrochloric acid. In the 3 i 
third, fourth, and fifth tubes place 15 c.c. of glycerine solu- 
tion which has been diluted previously with ten parts of 0.2 % 
hydrochloric acid to one of glycerine solution. Prepare the 
sixth tube in the same way as the third and then add 5 c.c. _ 
of concentrated hydrochloric acid. Prepare the seventh tube 

' 



PRINCIPLES OF DIGESTION 

in the same way as the third and then add 5 c.c. of caustic 
soda solution. Add to each of the seven tubes some minced 
white of egg, and shake it. Place Tubes 1, 2, 3, 6, and 7 in 
a temperature of 36 C. and keep at this temperature 
for twenty-four hours. Place Tube 4 in ice. Boil the con- 
tents of Tube 5, cool it and then keep it at 36 C. for 
24 hours. 

At the end of twenty-four hours describe the appearance ^ 
of all. the tubes. Does pepsin alone digest protein? What 
does 0.2 % hydrochloric acid alone do to protein? Why . ..> 
are both present in the stomach? What effect does cold 
have on gastric digestion? Why is much ice water bad for 
digestion? What does boiling do to gastric juice? What is O~" 
the effect of strong acid? strong base? Why is sodium 
bicarbonate given in cases of sour stomach? Can saliva act \tul 
on starch in the stomach? 1 Reason? ~fe v^Z^- c ^ v \ 

C. Effect of Gastric Juice on Other Nutrients. Prepare three 
tubes and add to each 10 c.c. of artificial gastric juice. To 
tube 1 add a piece of white of egg (control). To tube 2 add 
a piece of beef fat. To tube 3 add a little starch. Place at 
36 C. for 24 hours. At the end of that time examine. Does 
gastric juice digest fat? starch? 

D. Effect of Gastric Juice on Milk. To 10 c.c. of milk 
in a test tube add an equal volume of artificial gastric juice. 
What happens to the milk?^" "Remove some of the solid 
particles and test with Millon's reagent. Are they protein? j 
Let stand 24 hours at 36 C. Do the particles digest? 
Why is milk a good food? Save some of the particles for 
Ex. XLI. 

1 Owing to the slow mixing of the gastric juice with food in the 
stomach salivary digestion may continue there from 20 minutes to 40 
minutes after the food is swallowed. 

CALIFORNIA COLLEGE 
of PHARMACY 



68 EXPERIMENTAL PHYSIOLOGY 

XLI. PANCREATIC DIGESTION 

Apparatus. Alcohol extract pancreas or solution of pancreatin, 
0.5 % sodium carbonate solution, minced white of egg, biuret re- 
agent, starch paste, milk, blue litmus solution, 0.2 % HC1, KOH 
solution, concentrated HC1, test tubes, constant-temperature appa- 
ratus. 

Directions. A. Action of Pancreatic Juice on Protein. 
To a piece of minced white of egg in a test tube add 10 c.c. 
artificial pancreatic juice (1 volume alcoholic extract + 2 vol- 
umes 0.5 sodium carbonate solution, see Ex. XXXVIII). 
Place in a temperature of 36 C. and examine at intervals of 
10 minutes. Describe the changes you observe and compare 
with, the effects noted in Ex. XL, A. Does the white of egg 

ellx Test the final product with the biuret reagent : v Is 
it protein^ Repeat the above experiment, using the particles 
of milk curd obtained in Ex. XL, D. Do they digest? 

B. Action of Pancreatic Juice in Starch. To a little 
starch paste in a test tube add 10 c.c. artificial pancreatic 
juice. Place in a temperature of 36 C. and test portions 
with Benedict's or Fehling's solution at intervals of 10 
minutes. Describe the results. Does pancreatic juice 
digest starch? J^sssar flA , 

C. Action of Pancreatic Juice on Fat. To about 20 c.c. 
of milk add sufficient blue litmus solution to impart a deep 
blue color to the milk. Divide the milk into two equal por- 
tions and transfer these to test tubes. To one half add 

c.c. of boiled pancreatic juice (control) and to the other 
add 5 c.c unboiled pancreatic juice. Shake each mixture 
thoroughly and keep at 36 C. for a laboratory period. At 
the end of the time describe any changes that you observe. 
What does pancreatic juice do to milk fat? Cw^jhl/cL/ 





PRINCIPLES OF DIGESTION 69 

D. Conditions Affecting Pancreatic Digestion. 1 Prepare 
seven test tubes and into each pour 3 c.c. of alcoholic ex- 
tract pancreas and 2 c.c. of water. To these solutions add 
successively (a) 5 c.c. H 2 0; (6) 5 c.c. 0.2 % HC1; (c), (d), (e) 
5 c.c. 0.5 % Na 2 C0 3 ; (/) 5 c.c. concentrated KOH solution; 
(g) 5 c.c. concentrated HC1. Drop into each a piece of 
minced white of egg. Place tubes (a), (6), (c), (/), and (g) 
in a temperature of 36 C. Pack tube (4) in ice. Boil the 
contents of tube (e) and then place at 36 C. Tabulate the 
results at the end of an hour. Write a statement giving 
the conditions favorable and unfavorable to pancreatic diges- 
tion based upon your results. 



XLIL STUDY OF DIGESTIVE ACTION OF BILE 



Apparatus. Ox bile, milk, test tubes, pancreatic juice, blue 
litmus solution, constant-temperature apparatus. 

Directions. Prepare four test tubes as follows: Into each 
put 10 c.c. fresh milk. Add to tube 1, 10 c.c. of water. 
To tube 2 add 5 c.c. of bile and 5 c.c. of water. To tube 3 
add 5 c.c. of bile and 5 c.c. pancreatic juice. To tube 4 
add 5 c.c. pancreatic juice and 5 c.c. water. Shake well and 
place the four tubes at 36 C. after coloring each blue with 
the litmus solution. Let stand and note results. Does bile 
alone digest milk fat? Does bile hinder or help the pan- 
creatic digestion of milk fat? 

Let tubes 1 and 2 stand for several days. Does bile 
prevent the putrefaction of milk? 

State your conclusions as to the digestive power of bile 
as observed in the above results. 

1 This experiment may be repeated with starch paste or protein if 
desired, using the same method described for milk. 



70 



EXPERIMENTAL PHYSIOLOGY 



XLIIL MICROSCOPIC ANATOMY OF THE DIGESTIVE 
TRACT (OPTIONAL) 

Apparatus. Prepared slides of the cross sections of the walls 
of the esophagus (middle part), stomach (pyloric section), small 
intestine (injected blood vessels); compound microscope. 

Directions. Make drawings of each section studied and 
label the parts. See Figs. 30 and 31. 



nun. 




FIG. 30. Vertical Section 
of the Coats of the 
Stomach; d, surface of 
mucous membrane, and 
mouths of gastric folli- 
cles; ra, gastric tubuli, 
or follicles; mm, dense, 
connective tissue ; sra, 
sub-mucous tissue; cm, 
transverse muscular fi- 
bers; Im, longitudinal 
muscular fibers; s, fi- 
brous, or serous, coat. 




FIG. 31. Section of Injected Small Intestine 
of Cat: a, 6, mucosa: g, villi; t, their absorb- 
ent vessels; h, simple follicles; c, muscularis 
mucosse; d, sub-mucosa; e, e, circular and 
longitudinal layers of muscle; /, fibrous coat. 
All the dark lines represent blood vessels 
filled with an injection mass. 



PRINCIPLES OF DIGESTION 



71 



XLIV. TABULATION OF NUTRIENT DIGESTION 
(OPTIONAL) 

Directions. Fill out the following table from the results 
obtained in the preceding exercises. If a given nutrient 
is digested by more than one reagent, indicate it by sepa- 
rate entries for each in the table. 



NUTRIENT 


REGION OF ALIMENTARY 
TRACT DIGESTED IN 


DIGESTIVE REAGENT 


NAME OF DIGESTED 
PRODUCT 


Protein 








Protein 








Starch 








Starch 








Fats 








Fats 









BLOOD 

_/ 

XLV. GENERAL PROPERTIES OF BLOOD 

Apparatus. Glass slides and cover glasses, magnifier, microscope, 
needle, physiological salt solution (0.6 % solution), neutral carmi- 
nate of ammonia. 

Directions. Wind a handkerchief tightly around the 
thumb, just below the joint. Now bend the upper joint. 
The blood will collect on the top of the thumb just below 
the nail. Sterilize a needle by holding it a second in a flame, 
and prick the thumb just below the nail. The blood from 
the puncture may be easily and quickly transferred to a 
glass slide. 

A. With a magnifier examine a drop mounted as above. 
Is it all liquid? Is it the same color throughout? Describe 
the color at the edge of the drop. Let the drop remain on 
the slide for ten minutes and examine again. Is it liquid 
now? Prick at it with the needle point and describe its 
consistency. This formation is called a dot. Examine the 
puncture on the thumb with the magnifier. Has it stopped 
bleeding? What is the condition of the blood on the surface 
of the puncture? Does it resemble the condition of the drop 
on the slide? Bind up the thumb as before and flex the 
upper joint. Does the puncture bleed again? Wash off 
the clot with water. Does the bleeding begin again now? 
What is the advantage of this clotting action of the blood? 

B. Mount a drop of blood quickly, and examine at 
once with the high power of the microscope. Note the 
rouleaux of colored corpuscles. What is their color? Note 

72 



BLOOD 



73 



also the white or colorless corpuscles (colorless corpuscles 
tend to stick to glass; hence they will remain if the cover 
glass is pressed with a needle so that the current will drive 
the others aside, and they can then be more readily seen). 
What is the color of the liquid in which the corpuscles are 
floating? This liquid is called the plasma. Let this prepa- 
ration stand for fifteen minutes and then run under the 
cover glass a drop of strong solution of neutral carminate 
of ammonia. 1 This decolorizes the red corpuscles but brings 




FIG. 32. Blood Corpuscles: A, red corpuscles in rouleaux; a, a, colorless corpuscles 
(X 400); B, red corpuscles in focus; C, view of edge; D, three-quarters view; E, 
red corpuscle swollen with water; F, G, H, distorted red corpuscles. 

out the nuclei of the white corpuscles and the fibrin fila- 
ments. Draw some of the white corpuscles and note the 
shape of the fibrin filaments. Note how the entanglement 
of these filaments forms the foundation of the clot. 

C. Mount a drop of blood as in B, but before covering it 
with the cover glass, add a drop of physiological salt solu- 
tion. This causes the separation of the red corpuscles. 
Draw a surface view and an edge view of a red corpuscle 
under the high power. How do the red corpuscles differ 
in appearance from the white corpuscles? Have they a 
nucleus? 

1 A permanent mount may be made of this preparation if a little glycer- 
ine is allowed to diffuse under the cover glass and the cover slip is then 
cemented to the glass with gold size. 



74 EXPERIMENTAL PHYSIOLOGY 

XLVI. STUDY OF Ox OR HOG BLOOD 

Apparatus. Five-ounce bottles, fresh blood, egg beater, test 
tubes, food-testing materials, constant-temperature apparatus, com- 
pound microscope, slides and cover glasses, distilled water, dialyzer. 

Directions. Obtain from a butcher a quart or more of 
fresh-drawn blood. Divide this among the five-ounce bottles 
as follows : 

Bottle 1. Fill with fresh blood and cork so as to exclude 
all air. 

Bottle 2. Fill two-thirds full and leave uncorked. 

Bottles 3, 4, and 5. Fill two-thirds full and cork. 

Place the remainder of the blood in a basin and whip 
vigorously with an egg beater or twigs. Take off the stringy 
substance that collects on the beater, and wash it in water 
until it has lost its red color. Put it in Bottle 6 and add 
to it a little water. 

Pour the whipped blood into a suitable-sized bottle and 
label it " Bottle 7." Leave uncorked. 

A. Study of Coagulation or Clotting. Place Bottles 1 and 
2 in ordinary room temperature. Examine frequently for 
several days. In which bottle does the clot form quickest? 
Does the absence of air in Bottle 1 have any effect on the 
rate of clotting? 

Place Bottle 3 in a constant temperature of 36 C. and 
pack Bottle 4 in ice. In which does the clot form quickest? 
Does temperature affect the rate of clotting? 

Place Bottle 5 under the same conditions as 1 and 2 but 
shake from time to time. Does this affect the rate of 
clotting? 

Place Bottle 7 with 1, 2, and 5. Examine after three days. 
Has this blood clotted? What is missing in it? (The sub- 
stance is called fibrin.) 



BLOOD 75 

Summarize the conditions best suited to clotting. 

B. Study of the Clot. Pour off the liquid from all the 
bottles in which a clot has formed and place it in Bottle 8. 
(This liquid is called serum.) Then break one of the bottles 
containing a clot and remove the clot entire. What is its 
shape? color? consistency? Cut off a thin slice of it and 
examine it under the microscope. What parts can you 
distinguish? Does it contain any corpuscles? The jelly- 
like substance is to be found in its pure state in Bottle 6. 
Examine some of this fibrin. What is its color? Test it 
for protein. What is the result? Explain in a few words 
the formation of a clot and the part played in its formation 
by the fibrin and the corpuscles. 

C. Study of the Serum. Examine the liquid in Bottle 8. 
What is its color? Why is it not red? 

Test a little with iodine solution for starch. Since starch 
must be digested before it can be absorbed into blood, why 
should you expect this result? 

Test some of the serum with Benedict's or Fehling's 
solution for the presence of grape sugar. Do you get a 
strong test? What does this result suggest as to the amount 
present? 

Burn a little serum on a piece of platinum foil. Does it 
contain any mineral matter? 

Place a drop on a piece of unglazed paper and let it evap- 
orate. Does it leave a grease spot? 

Heat a little serum and test for proteid. Can fibrin be 
present? Explain the result of the test. What use is made 
of the nutrients present in serum? How do they get into 
the serum? What function of the blood does the presence 
of these nutrients suggest? 

D. Study of Defibrinated Blood. Examine the contents 



76 EXPERIMENTAL PHYSIOLOGY 

of Bottle 7. How does this blood differ from fresh blood? 
from serum? 

Place some of this blood in the dialyzer. Fill the outer 
jar with distilled water. Does the color of the water in the 
outer jar change? After a time test the water in the outer 
jar for protein, grape sugar, minerals. What part of the 
blood osmoses? 

Fill a bottle half full of defibrinated blood and shake it 
vigorously. Does it change in color? What was mixed 
with the blood by shaking the bottle? 

XL VII. CRYSTALLIZATION OF HAEMOGLOBIN FROM 
BLOOD (OPTIONAL) 

Apparatus. Defibrinated blood, microscope slide, cover glass, 
compound microscope. 

Directions. To one drop of defibrinated blood on a 
slide add one drop of water. Mix the two drops thoroughly, 
but use care not to spread them.. Allow the mixed drops 
to dry in the air until a comparatively wide dry border is 
formed. Cover with cover glass and look for crystals of 
haemoglobin with the compound microscope. 

XLVIIL DETECTION OF BLOOD IN BLOOD STAINS 

(OPTIONAL) 

Apparatus. Blood-stained cloth, evaporating dish, compound 
microscope slides and cover glasses, solid sodium chloride, lamp, 
glacial acetic acid. 

Directions. A. Spread the cloth in an evaporating 
dish and moisten thoroughly with water. Squeeze the 
water out into the dish. Then examine a drop of this liquid 
with the microscope for blood corpuscles. 

B. Hcemin Test (Teichman's). Place a drop of the cloth 



BLOOD 77 

extract on a microscope slide. On a second slide place a 
drop of blood obtained as described in Ex. XLV (control). 
To each drop add a minute grain of sodium chloride and 
carefully evaporate to dryness over a low flame. Put a 
cover glass in place, and run under it a drop of glacial acetic 
acid. Warm gently until gas bubbles form. Add now 
another drop of the acetic acid, cool the preparation, ex- 
amine under the microscope, and describe the crystals 
(haemin crystals) which" form. Would this be an absolute 
test for blood? for human blood? 



CIRCULATION AND THE BLOOD SYSTEM 



XLIX. PROPERTIES AND LOCATION OF ARTERIES AND 

VEINS 

Apparatus. A watch with a second hand, a needle, a chemical 
thermometer. 

Directions. Examine the back of the hand and wrist 
and locate the dark-colored veins. Is the blood this color? 
Place your finger on a vein. Can you feel any motion? Is 
there any difference in the size and prominence of the veins 
when you exercise violently? Why should you expect this 
result? 

Find your pulse on the palm side of the wrist. Count its 
beats and record the number per minute. Test this rate at 
various times of the day. Is it uniform at all times? Test 
your body temperature at the same time by placing the bulb 
of the chemical thermometer under the tongue. Does the 
temperature vary with the pulse rate? Does either increase 
after violent exercise? If food is burned up by exercise, and 
blood contains oxygen and food, how do you account for 
these effects? 

Examine other parts of the body for veins and arteries 
(pulse always indicates the presence of an artery). Which 
are most numerous on the surface? Which are best pro- 
tected? The bleeding of a cut artery is much more difficult 
to stop than that of a vein, owing to its pulsation. 

Examine the skin on the back of the hand between two 
veins. Can you see any blood vessels? Place the finger 

78 



CIRCULATION AND THE BLOOD SYSTEM 



79 



on this part. Can you feel any pulse? Prick through the 
skin at this point with a sterilized needle. Does the punc- 
ture bleed by spurts or steadily? The small blood vessels 
filling these places are called capillaries on account of their 
small size (capillus = a hair). They connect the veins and 
arteries. 

L. CIRCULATION IN A FROG'S FOOT 

Apparatus. Compound microscope, cover slip, live frog, shingle, 
wet absorbent cotton, and cloth. 

Directions. Bind a live frog in wet absorbent cotton, 
leaving one leg extended. Fasten the frog, so bound in place, 




Fia, 33. Capillary Circulation in the Web of a Frog's Foot, X 100: a, b, small 
veins; d, capillaries in which the corpuscles are seen to follow one another in single 
series; c, pigment cells in the skin. 



80 EXPERIMENTAL PHYSIOLOGY 

on a frog board (a piece of shingle with a hole the size of a 
cover slip at one end). Stretch the web of the foot over the 
hole in the board. Fasten it securely, with the stretched 
web as level as possible. Mount this board on the micro- 
scope stage in such a way as to bring the web-covered hole 
under the objective of the microscope. With a pipette 
place a drop of water on the top of the web, and cover with 
a piece of cover slip. Illuminate in the usual way and focus 
first with the low and then with the high power. 

Note the network of blood vessels and the slow-moving 
stream of corpuscles within them. Are the corpuscles the 
same size and shape as those in the human blood? Is 
there only one kind? Observe that in some of the blood 
vessels the blood moves in spurts at regular intervals. What 
kind of vessels are these? Does the blood in these flow from 
or toward the body? Follow the course of the blood from 
these into the smaller tubes where the corpuscles move in 
almost single file. Do these show pulsations? Trace the 
flow from these into larger vessels where no pulsation is 
evident. Note the direction of flow in these tubes. What 
is the name of these tubes? Define artery, vein, and capillary 
in terms of the direction of blood flow. 



LI 



. MINUTE STRUCTURE OF ARTERIES AND VEINS 
(OPTIONAL) 



Apparatus. Prepared slides of cross sections of arteries and 
veins, compound microscope. 

Directions. Note that both artery and vein have three 
coats: a lining of epithelial cells called here endothelium, a 
middle layer consisting of a mixture of muscle and elastic 
fibers, and the outside layer or coat of connective tissue 



CIRCULATION AND THE BLOOD SYSTEM 81 

bundles. Make careful drawings of the two preparations, 
showing the location and form of these layers, and label 
the above-mentioned parts. 
In which of the two 
forms of blood vessels is 
the elastic and muscular 
coat thickest? Why 
should you expect this 
condition from the method 

of flow of 'blood in each? IM^feag^MW-d 
What is the special ad- 
vantage of the elastic fi- 
bers in the artery? In 

What Way do they aid tO FIG. 34. Cross Section of an Artery: a, 
l U ~^11^,.:~~ -Gll^ endothelium; 6, muscular layer; c, con- 

keep the capillaries filled nective tiggue; df small artery to nourish 

at the end of an artery large one. 

pulsation? Is the pressure greatest in arteries or in veins? 





LIL STRUCTURE OF THE HEART 

Apparatus. Sheep's heart from the butcher with pericardium 
attached, bristle seekers, dissecting instruments. 

Directions. Locate the parts named below, and make 
drawings to show their position. 

A. Note that the heart moves easily inside a loose sac. 
Cut this pericardium open and observe its slippery inner 
coat. Note a similar coat on tiie outside of the heart. 
What lies between these two coat$?< This liquid and the 
slippery coats prevent friction when the heart pulses. 

B. Carefully cut away the pericardium from the blood 
vessels, and the fat from the surface of the heart. Locate 
the aorta, vence cavce, pulmonary veins and artery, and push 
bristle seekers through these blood vessels into the heart. 



82 



EXPERIMENTAL PHYSIOLOGY 



C. Examine the outside of the heart and locate the follow- 
ing parts of the heart proper : right and left auricles, right and 




ZFC, 



Fia. 35. Heart in position with pericardium removed (Human): TV, trachea; 
L, lungs; RA, LA, right and left auricles; RV, LV, right and left ventricles; Ao, 
aorta (two branches); SVC, JVC, superior and inferior venae cavae; PA, pulmonary 
artery. 

left ventricles. By right and left are meant the parts of the 
heart that are right and left in regard to the position of the 
heart in the body. Which parts have the thickest walls? 



CIRCULATION AND THE BLOOD SYSTEM 



83 



The walls are made of muscle, and these thick-walled parts 
do the pumping. 

D. Cut off carefully the front walls of the right auricle 
and ventricle. By means of the bristles locate the entrance 




FIG. 36. Right Auricle and Ventricle (Sheep): RA, RV, right auricle and ven- 
tricle; IVC, SVC, inferior and superior venae cavse; a, b, bristle seekers showing 
connections between auricle and ventricle, auricle and vena cava; PA, pulmonary 
artery; to, tricuspid valve; pp, papillary muscle; sv, semilunar valves. 

into the auricle of the inferior and superior vence cavce, and 
the entrance into the ventricle of the pulmonary artery. 
Find the connection between the auricle and the ventricle 
and note the tricuspid valve that closes this entrance. Lo- 
cate also the chordae tendince that attach this valve to the pap- 
illary muscles on the surface of the heart. What is the effect 



84 



EXPERIMENTAL PHYSIOLOGY 



of the contraction of the ventricle on the action of this 
valve? Note finally the semilunar valves at the entrance to 



Ao 




FIG. 37, Left Auricle and Ventricle (Sheep); a, 6, c, Bristle seekers showing con- 
nections of auricle with ventricle, of auricle with veins, and of ventricle with arteries; 
PV, pulmonary veins; pp, papillary muscles; mv, mitral valve; PA, pulmonary ar- 
tery; Ao, aorta; SVC, superior vena cava. 

the pulmonary artery. How does their arrangement pre- 
vent the backward flow of blood into the heart? 

E. Cut off the front walls of the left auricle and ventricle 
in the same way. Have they any connection with the right 
side of the heart? Locate, with the aid of the bristles, the 



of PHARM 

CIRCULATION AND THE BLOOD SYSTEM 85 

entrance of the pulmonary veins. How many enter the 
auricle? Find the entrance from the auricle to the ventricle, 
and the mitral valve which guards this entrance. Does it 
show chordae tendinse and papillary muscle attachments? 
How does it differ in shape from the tricuspid? Locate the 
semilunar valves at the entrance of the aorta. 

Make a careful diagram of the course of circulation through 
the heart to the lungs and back to the heart and body. 





THE BODY SKELETON 



LIIL STUDY OF THE SKELETON 

Apparatus. Human skeleton. 

Directions. Tabulate as follows the various classes of 
bones : 



KIND OP BONE 


No. 


NAME OF BONE 


LOCATION IN BODY 


FUNCTION 


\\ 












LIV. GROSS STRUCTURE OF BONES 

Apparatus. Fresh rib, thigh bone, and dorsal vertebra; saw, 
needle. 

Directions. A. The Rib, a flat bone. Draw the bone 
from the flat side. What is found at the ends of the bone? 
What is the color, consistency, and function of this sub- 
stance? Bend the bone. Is it flexible? Pick off the mem- 
brane (periosteum) that covers the bone. Does it separate 
easily from the bone? Does it tear easily? Are all parts 
of the bone protected by this covering? 

Saw the rib across. Examine the section and draw it, 
labeling the parts in the order in which they occur. What 
part is periosteum? hard bone? spongy bone? marrow? 
Examine the central marrow. What is its color? How 

86 



THE BODY SKELETON 



87 



does it feel? Heat some in water in a tube. What collects 

on the top of the water? 

^ B. The Thigh Bone, or Shank, a long 

i^*\ bone. Draw the bone, and shade with 
different colors the parts that are covered 
with cartilage and with periosteum. What 
is the function of the enlarged heads of 
this bone? Of what advantage is it that 
they are irregular in surface? 

Saw the bone lengthwise, draw, and 
label the parts. In what portion of the 
bone is the marrow most plentiful? Is 
the shaft solid? What is the advantage 
of this condition? 

C. The Dorsal Vertebra. Draw a dor- 
sal vertebra from the side and from the 
top. With the aid of the diagram locate 
the following parts: The body of the 
vertebra, spinous process, transverse proc- 
esses, spinal cavity, rib articulations, ver- 




3 



Fia. 38. Thigh Bone, Fia. 39. A Dorsal Vertebra: 1, centrum or body; 2, 
in Longitudinal Sec- spinous process; 3, spinal cavity; 4, transverse process; 
tion. 5, rib articulation; 6, vertebral articulation. 

tebral articulations. How are the articulations protected? 
What is the function of the processes? 



88 EXPERIMENTAL PHYSIOLOGY 

LV. COMPOSITION OF BONE (OPTIONAL) 

Apparatus. Two clean ribs, a soup bone split in two, 20% 
hydrochloric acid, bottle big enough to hold rib, evaporating dish, 
food-testing materials, Bunsen burner. 

Directions. A . Place one of the ribs in the bottle and 
fill the bottle with the 20 % hydrochloric acid. Let it stand 
for a few days. At the end of that time examine it. Has it 
changed in shape? Take it out of the bottle and bend it. 
What power has it lost? What substance is left? Hold a 
little of it in the flame. Does it burn? Pour a little of the 
acid from the bottle into the evaporating dish and evapo- 
rate to dryness. What kind of substance is left? What 
material did the acid dissolve out of the bone? 

B. Burn the other rib. What is the shape of the part that 
is left? Is it flexible? Put some of it in the acid. Does it 
dissolve? Name the two main constituents of bone. 

C. Cover the split soup bone with water and gradually 
bring to a boil. Strain off the liquid and let it cool. What 
do you find floating on the surface? What forms as it 
cools? What is the character of this substance? Test for 
nutrients. 




^ 

LVI. STRUCTURE OF A JOINT 
Apparatus. Fresh leg joint of lamb or veal, scalpel. 

Directions. Examine the tissue that binds ttie two 
bones together. What is the character of these bands, or 
ligaments? Are they flexible? How do they control the 
direction of movement of the bones? Cut off the ligaments 
with a scalpel. Note the liquid found within. What does 
it look like? (It is a lubricant called synovial fluid.) 

Examine the ends of the bones. With what are they 



THE BODY SKELETON 



89 



covered? Press this surface. Is it elastic? What is the 
advantage of this? Is the surface smooth? Of what ad- 



Pelvic Bone 

Synovial Membrane 

Head of Femur 

Round Ligament 

- f( T\ : Capsular Ligament 




FIG. 40. A Joint. 



vantage is this? What is the reason for the enlarged ends of 
the bones? for their irregular surfaces? 



-f 




LVIL FORMS OF JOINTS 

Apparatus. The human skeleton. 

Directions. Examine the following joints and describe 
the range of motion of each : Knee, elbow, vertebral, shoulder, 
hip, jaw, head, and spine, bones of the skull, ribs. 

Name the bones united in each case and classify the joints 
under the following names: hinge, ball and socket, gliding, 
rotary, dovetail, symphysis. 

Which of the above are movable joints? fixed? 




MUSCLES AND MOTION 
LVIII. DISSECTION OF THE MUSCLES 

Apparatus. - The body of the rat used in Ex. XXXVI (any 
other animal will serve the purpose, and if a demonstration is desired 
for the study of the leg muscles the leg of a sheep may be substi- 
tuted), scalpel. 

Directions. Carefully cut off the hind leg of the rat, 
close to the hip joint, and remove the skin. Note the 
muscles covering the bones and the glistening white muscle 
sheath (perimysium) covering each muscle. At the ends 
of the muscles note the white tendons. Are the muscles 
attached directly to the bones? The end of the muscle that 
moves most in contraction is called its insertion; the one 
that moves least, its origin. Where are the tendons most 
numerous? How does this arrangement avoid clumsiness 
in the foot? Compare with- the arrangement in your own 
hand and foot. Is it the same? 

Separate the muscles without cutting them, and pull 
on each to determine what part of the leg it controls. 
Muscles that extend a joint are called extensors, those that 
bend it are called flexors. Note that all these muscles have 
a thick center, or belly, and tapering ends with tendons 
attached at the ends. Those muscles with two tendons at 
the origin are called biceps; those with three, triceps. Ex- 
amine one of these tendons. How is it different from a 
muscle? Is it elastic? Why should you expect this from 
its use? 

Remove the skin from the sides of the body. How do 

90 




MUSCLES AND MOTION 91 

the underlying muscles differ from the leg muscles? Have 
they tendinous ends? What two classes of muscles based 
upon their form can you name from your study? Mention 
some other parts of the body where the different kinds of 
muscles can be found. 

Preserve the rest of the rat's body for future use. 

/ 

LIX. GROSS STRUCTURE OF MUSCLE 

Apparatus. A bellied muscle from the rat or frog (a piece of 
fresh beef will serve), needles, compound microscope and slides, food- 
testing materials. 

Directions. Boil the muscle in water for a few moments 
and pick it to pieces with the needles. Note that it sepa- 
rates easily into bundles. Why is cooked beef more easily 
chewed than raw? Examine the perimysium covering the 
bundles. What sort of tissue is it? Describe its appear- 
ance. What purpose does it serve? Place one of these 
bundles in a drop of water on a slide and with the needles 
tear off the perimysium and tease the bundle into fibers. 
Examine one of these fibers under the low power of the 
microscope. Note its covering (sarcolemma) and its striated 
appearance. All muscles under direct nerve control (volun- 
tary muscles) show this striation. (For the minute anatomy 
of this fiber see Ex. XXX.) 

Apply the xanthoproteic and other nutrient tests to pieces 
of the muscle. From the strength of the various reactions, 
what is the main constituent of muscle? Why does an 
athlete require a diet rich in protein? 

LX. NERVE MUSCLE PREPARATION (OPTIONAL) 

Apparatus. Put a frog in a bottle or jar, pour in a little chloro- 
form, and cork the bottle. As soon as the frog is still, remove it 
from the jar and, with a scalpel, sever the spinal cord just back of 
the skull. With a wire, destroy the brain and spinal cord. Dissect 



92 



EXPERIMENTAL PHYSIOLOGY 



away a hind leg; remove all the muscles except the gastrocnemius, 
and separate this at its lower attachment. Fasten the femur strongly 
in a clamp. With a pointed glass rod separate the sciatic nerve at 
the upper part; do not touch it with metal instruments. Into the 





FIG. 41. sc, sciatic nerve; g, gastrocnemius; ad, b, etc., other muscles. 

lower end of the muscle insert a hook and connect it with a lever as 
in Fig. 42. Connect a copper wire, insulated except at the end 
which is to be used as an electrode, with each pole of a battery of 
two dry cells. For convenience a key of some kind may be inserted 
in the circuit to make and break. 

Directions. Touch the free end of the nerve with the 
two electrodes. What happens to the muscle? Record the 
extent of the action. This shows that nerve stimulation may 
cause the muscle to move. Keeping the electrodes in con- 
tact with the nerve, note whether the action continues. 



MUSCLES AND MOTION 



93 



Remove the electrodes. What happens? Repeat this proc- 

ess several times and mark the distance that the lever moves 

each time. Is it the 

same? Does the action 

increase or decrease? 

This result illustrates 

what may happen from 

overstimulation; namely, 

muscle fatigue. 

Repeat the experiment, 
applying the current to 
the body of the muscle 
instead of the nerve. 
Compare with the results 
of the first experiment as 
to the extent and strength 
of the action. 

In both of the above experiments what property of the 
muscle is stimulated? Why is muscle called contractile tissue? 




FIG. 42. Nerve Muscle Preparation: s, set 
screw; c, clamp; /, femur; m, gastrocnemius; 
n, sciatic nerve; h, hook; /, lever; , elec- 
trodes; 6, battery. 



LXI. STUDY OF LEVER ACTION (OPTIONAL 
Apparatus. Wooden bar with holes near the ends and at the mid- 
dle (exactly halfway between the end holes), spring balances. 

Directions. A. Support the bar by the middle hole (see 
Fig. 43, A) and trim the bar till it balances level. Fasten 
the spring balances in the two end holes. Pull down on 
each, keeping the bar horizontal. Compare the pulls regis- 
tered by the balances. What is their relation? Attach one 
balance halfway between the end and middle holes, keeping 
the second balance in the other end hole. Pull until the bar 
is level as before. What is the relation of the registered 
pulls now? Verify the following law by changing the posi- 
tion of the two balances. 



94 



EXPERIMENTAL PHYSIOLOGY 



Weight X perpendicular distance from the pivot equals 
pull X perpendicular distance from the pivot. (Perpendic- 
ular distance is measured from the pivot at right angles to 
the direction in which the force is acting.) 

This arrangement of lever is called a lever of the first class. 

B. Support the bar by one end hole, and at the extreme 
end attach a weight so that the bar will balance level; then 

f \ 





FIG. 43. Forms of Levers: A, 1st class; B, 2d class; C, 3d class; W, weight; F, 
fulcrum or pivot; P, pull. 

insert the balances in the other two holes (see Fig. 43, B). 
Pull down with the one nearest the pivot (weight), and up 
with the one at the end (pull) . Record the pull and weight 
when the bar is level, measure the distances from the pivot, 
and see if the law of A still holds. This arrangement is 
called a lever of the second class. 

C If the pull nearest the pivot be called the pull and the 
other the weight, the arrangement is called a lever of the 
third class (see Fig. 43, C). 

LXIL LEVEKS OF THE BODY (OPTIONAL) 

Directions. A . Locate on the upper arm the biceps 
muscle, or flexor of the arm. Where is it attached to the 
forearm and how far (perpendicular distance) from the 
elbow? Measure the perpendicular distance from the elbow 



MUSCLES AND MOTION 95 

to the center of the palm. If now we put a weight of ten 
pounds in the palm and bend the arm, what class of levers 
is illustrated? How much force is required on the part of 
the muscle to raise ten pounds' weight? By selecting 
different weights to lift, determine the maximum strength 
of the biceps muscle. What muscle is used in striking an 
outward blow with the fist? Where is it located and in- 
serted? Note that the flexors and extensors in other parts 
of the body are usually arranged in pairs. 

B. Examine the relation of the muscle, weight, and pivot 
in the following cases, and tell which class of lever each 
illustrates: Jaw action in chewing, flexing of the fingers, 
movement of the legs in kicking, bending the body, move- 
ment of the foot about the ankle (see Fig. 43). 

NOTE. The instructor can suggest other problems of the above 
nature to make clear the laws of lever action. 



RESPIRATION 




LXIIL DISSECTION OF A RAT'S LUNGS 

Apparatus. Body of the rat used in Exs. XXXVI and LVII, 
scalpel, glass tube of one-eighth inch diameter. 

Directions. Remove the skin from the surface of the 
ribs and throat. Examine carefully the muscles between 
the ribs (intercostals) . Seize the base of the breastbone and 
move it up and down. Notice the motion of the inter- 
costals during this process. 

Insert the glass tube in the top of the windpipe through 
the throat opening, and blow gently through this tube. 
Observe the motion of the ribs and the motion of the muscu- 
lar diaphragm that forms the partition between the abdom- 
inal and the thoracic cavities. Press the diaphragm up with 
the finger and note that air is forced out of the tube. 

Now cut the ribs where they join the breastbone, and press 
them back to expose the organs of the cavity. Sketch the 
position of the lungs and heart. Compare with Fig. 35, 
page 82. Note the texture of the lungs' and observe the 
windpipe (trachea) with its cartilage rings. (These are nec- 
essary to prevent collapse of the tube.) How is the windpipe 
connected with the lungs? 

Carefully dissect out the lungs and windpipe and float 
them in water. Cut them at the entrance of the windpipe 
and trace out the bronchi and their branches. How do these 
branches end? (This large amount of branching allows the 

96 



RESPIRATION 



97 



air to be brought in contact with very many small blood 
vessels, through the walls of which oxygen is absorbed by 
the blood.) 

LXIV. MECHANICS OF RESPIRATION 

Apparatus. A glass bell jar open at the top, a glass tube with 
a toy balloon firmly bound to one end, a stick with a knob, a piece 
of sheet rubber, a one-holed stopper to fit top of bell jar. 

Directions. Pass the tube 
through the stopper and seal 
it in place with wax. Insert 
the stopper in the top of the 
bell jar with the balloon inside 
the jar. Tie the knob into 
the center of the rubber sheet 
and fasten the latter tightly 
across the base of the bell jar, 
leaving the stick outside to 
serve as a handle. With this 
arrangement the tube corre- 



Glass 




Handle 



Bel/Jar 
^Balloon 



~ffubber 
Diaphragm 



sponds to the trachea, the bal- FrQ - 44 - Apparatus to illustrate 

breathing movements and their 
effect upon the lungs. The rubber 
diaphragm corresponds to the dia- 
phragm in the body; the handle to 

the jar to the thoracic cavity. 
Now move the handle down- 



loon to the lungs, the rubber 
sheet to the diaphragm, and 



the tendon; the balloon to the 
lungs; the tube to the trachea; the 
bell jar to the walls of the thorax. 
As the handle is lowered the air 
flows down the tube and inflates 
the balloon. 



ward so as to stretch the 

diaphragm. What happens to 

the balloon? What causes 

this action? Move the handle upward. What happens to 

the balloon now? Why? How does the diaphragm secure 

rhythmic inhaling and exhaling, i.e., inflow and outflow of 

air? 




98 EXPERIMENTAL PHYSIOLOGY 

LXV. STUDY OF EXPIRED AIR 

Apparatus. Chemical thermometer, lime water, test tube, glass 
tube, large-mouthed bottle, pneumatic trough. 

Directions. A. Temperature. Breathe on the bulb of 
the thermometer and determine the temperature of the ex- 
pired air. Place the bulb under the tongue and determine 
the body temperature. How does the temperature of the 
expired air compare with that of the body, or blood tem- 
perature? Test this on several successive days and note 
whether the temperature varies with the external temperature 
or is constant. 

B. Composition. Breathe on a piece of glass. What col- 
lects on the surface? Does expired air contain more or less 
moisture than inspired air? 

Fill the test tube half full of limewater and blow the breath 
gently through it by means of the glass tube. What change 
takes place in the limewater? What does this indicate? 
(See Ex. VIII.) 

Fill the bottle with expired air by the method of Ex. II. 
Turn the bottle mouth upward and introduce a lighted 
match into it. Does the match continue to burn? What 
does this indicate? (Air expired in ordinary breathing has 
lost about one-fourth of the oxygen contained in the air 
inspired.) 




EXCRETION 



LXVI. STUDY OF A LAMB'S KIDNEY (OPTIONAL) 
Apparatus. A fresh lamb's kidney with its capsule of fat, scalpel. 

Directions. Carefully remove the outer layer of fat and 
the membranous inner capsule. What is the function of 
this material? (A dissection of the rat makes a good 
demonstration of the location of 
the kidneys and their relation to 
ureter and bladder.) Cut the 
kidney lengthwise so as to split 
the ureter where it emerges from 
the concave side. On the cut 
surface make out the pale inner 
striated medulla and its pyramids 
of Malpighi, the outer cortex, and 
the intermediate layer between the 
two. Note also the enlarged upper 
end, or pelvis, of the ureter; the 
cavity, or sinus, into which it 
opens; and the tubes, or calices, 

i . i . . . T FIG. 45. Diagram of a Longitu- 

between the projecting pyramids. dinal Section of a Kidney: flf 
Note also the entrance of the 
renal artery into the kidney, and 
the renal vein, just above the 

ureter. From the accompanying Fig. 45 make out the 
parts which act in removing the waste. (The artery brings 

99 




renal arteiy; c, capillaries; g, 
glomerulus; t, uriniferous tubule; 
, renal vein. 




100 EXPERIMENTAL PHYSIOLOGY 

in the blood, which gives up its waste in the glomerulus. 
This waste is collected by the tubule and emptied by it into 
the ureter. The capillaries collect the blood which has been 
cleared of its waste, and return it to the vein.) 

NOTE. Prepared sections of injected and stained cortex may be 
shown and the following parts demonstrated: Malpighian bodies, 
uriniferous tubules, and capillaries. 

LXVIL STUDY OF THE SKIN 

Apparatus. Prepared slide of epidermis (that from the sole of 
the foot preferred, from its thickness), a vertical section of a hair, 
compound microscope, needle, scissors. 

Directions. A. Surface Study of the Skin Layers. Ster- 
ilize a needle by holding it in a flame for a moment. Run it 
carefully under the thin outer layer of skin at the base of 
the thumb. (This layer is called the cuticle or epidermis.) 
Does the wound cause any pain? Are there any nerves in 
this layer? Does the wound bleed? Does the epidermis 
contain any blood vessels? With the needle tear off a little 
of this epidermis. What is its color? consistency? Where 
is it thickest on the hand? Why? Where else on the body 
do you find similar thickening? 

What is the color of the skin layer (dermis) under this 
epidermis? Prick it with the needle. Is it sensitive? 
Does it contain blood vessels? Examine its surface and note 
that it is ridged. A magnifier will show that these ridges 
are made up of a series of points, or papillaz. (Each papilla 
marks the end of a nerve of touch. These nerve endings 
are called on that account tactile organs; see Fig. 46.) Pick 
up a little of the skin between the fingers. Is it attached 
to the underlying muscles? About how thick is it on the 
back of the hand? on the base of the thumb? 



EXCRETION 



101 



B. Microscopic Study of a Section. Study the prepared 
slide, under the high power. Note the layer character of 
the epidermis, the papillae with their blood vessels, the coiled 
sweat glands and their ducts (thick sections show these 
best). Sketch and label all parts of your drawing as in 
the diagram. 



Sweat-Duet 



Horny layer <j ; 
Pigment layer 




Tactile Organ 
Nerve 
Mood Vessels 



FIQ. 46. Diagram of Skin Section. 



Compare the action of the sweat glands with that of 
the tubuli uriniferse (uriniferous tubules) of the cortex 
of the kidneys. When do we perspire most? Why does 
exercise increase the amount? What is one function of 
the skin? 

C. Study of Skin Modifications, (a) Hairs. Note the 
location of hair on the head. What is its function? Ex- 
amine one of the hairs on the back of the hand. Cut it. 



102 



EXPERIMENTAL PHYSIOLOGY 




Is it sensitive? Pull it. Where is 
the sensitive portion located? 
Where is the seat of growth? 
What part of the skin is it most 
like? 

Study the slide showing a ver- 
tical section of a hair under the 
low power of the microscope. 
Note that the hair is imbedded at 
the base in a skin follicle, and 
grows from a skin papilla at the 
bottom of this follicle. Note also 
the sebaceous or oil glands that 
serve to coat the hair with oil. 

(6) Nails. Make a drawing of 
your finger nail, showing all areas. 
What parts are attached to the 
skin? Why is the part under the 
nail called the "quick " ? What is 
one function of the nail? Cut 
it. Is it sensitive? Pull it. 
Where is its sensitive part located? 
How does it compare with the hair 
in this respect? Cut a nick in it 
and examine it from day to day. 

D eS !t chan e position? Where 



Fia.47.-Hair-foiricleinLongi- 

tudinal Section: h, hair shaft, does the growth of the nail OCCUr? 
showing its medulla or core: TI u i j. 11 ji ? , / 

s, sebaceous gland; w, sheath Tabulate all the functions of 

of skin; /.fatty tissue. (At the hairs, nails, and skin that you 

base of the hair is seen the i i j 

papiiia that forms it.) have learned. 




NERVOUS SYSTEM 



LXVIII. DISSECTION OF SHEEP'S BRAIN 

Apparatus. Sheep's head, bone forceps, hammer, scalpel, needle, 
forceps, 50 % alcohol. 

Directions. A. To Remove Brain from Skull. Strike 
the top of the skull with the hammer so as to crack the 
bone, but not to force it into the brain, and then carefully 
remove the pieces with the 
bone forceps. Be careful not 
to injure the underlying mem- 
brane (dura mater) which lines 
the skull and covers the brain. 
After the top of the skull 
is removed slit this dura 
mater around the edge, and 
remove it, exposing the brain. 
Note that over the surface 
of the brain is another mem- 
brane, the pia, mater. Now 
carefully lift the brain from 

thp flfifir nf thp Qlrnll Kpo-in- FlG ' 48. Upper Surface of Brain (Hu- 

ucuii, begin man) . j 2> two halveS) Ol hemispheres> 

ning at the front. Notice of cerebrum; 3, 3, longitudinal fissure. 

that it is bound by nerves and portions of the dura mater. 
Cut these nerves, leaving as long ends as possible, and do 
not cut off the olfactory lobes which are on the under side 

103 




104 EXPERIMENTAL PHYSIOLOGY 

of the brain. Place the brain in 50 % alcohol to harden, 
for several days. 1 

B. The Coverings of the Brain. Tear off a little of the 
dura mater with the forceps. Doesit tear easily? Are 
both sides of it smooth? Where are its blood vessels? 
What do they feed? 

Pick up a little of the pia mater (brain cover) with the 
needle point. Is it thicker or thinner than the dura mater? 
Where are its blood vessels? What do they feed? What 
are the functions of the three coverings of the brain? 

C. The External Parts of the Brain. Examine the top of 
the brain. Note the two convoluted hemispheres into which 
the fore brain (cerebrum) is divided by a fissure (the longi- 
tudinal fissure). Back of this appears the wrinkled surface 
of the hind brain (cerebellum). Is this divided? 

Turn the brain over and examine the lower surface. 
Note the olfactory lobes on the front part of the hemispheres. 
What is their function? Back of these locate the optic 
nerves, and note how they cross to form a chiasma } so that 
the right eye is controlled by the left hemisphere, and vice 
versa. Just back of this may be seen the pons, or bridge, 
that connects the two sides of the cerebellum, and, coming 
out in front of it on each side, the stalks (crura cerebri), which 
spread out into the two hemispheres of the cerebrum. Note 
that the stalks are the forward projections of a conical spinal 
bulb which comes between the cerebellum and the pons and 
is continued backward into the spinal cord. This bulb is a 
part of the hind brain, and is called the medulla. All along 
the under side of the brain are located the cranial nerves, 
occurring in pairs. Beginning at the front, locate the pairs 
named in the following table : 

1 Preserve the skull, with eyes, for use in Ex. LXXV. 



NERVOUS SYSTEM 



105 



Olfactory Bulb 

{ to which is attached 
the Olfactory Nerve) 

Pituitary Body _____ 

Optic Nerve 

Optic Chiasma 

Oculomotor Nerve . 

Trochlear Nerve 

Trigeminal Nerve 

Pons Varolii 

Abducens Nerve 

Facial Nerve 

Auditory Nerve 

Glossopharyngeal Nerve 

Vagus Nerve 

Spinal accessory Nerve 

Hypoglossal Nerve- - 

Medulla Oblongata 

First Spinal Nerve 

Cerebellum 

Spinal Cord 

Second Spinal Nerve 




FIG. 49. Under Surface of Brain (Human). 



NAME 


FUNCTION 




1st pai Olfactory 


Smell Sensory 




2d pai Optic 


Sight Sensory 




3d pai Oculomotor 


Eye Muscles Motor 




4th pai Trochlear 


Eye Muscles Motor 




5th pai Trigeminal 


Facial Sensory and Motor 




6th pai Abducens 


Eye Muscles Motor 




7th pai Facial 


Motor, mainly 




8th pai Auditory 


Hearing Sensory 




9th pai Glossopharyngeal 
10th pai Vagus 


Tongue and Throat Sensory and Motor 
Thorax and Abdomen^ Sensory and Motor 


llth pai Spinal Accessory 
12th pair Hypoglossal 


Motor 
Tongue Motor 





D. Vertical Section (right side). Cut the brain through 
lengthwise, parallel to the line of the longitudinal fissure, but 
one-sixteenth of an inch to the left of this line in order not 
to cut the septum. Examine the right side. Note the 



106 



EXPERIMENTAL PHYSIOLOGY 



white, fibrous body (corpus callosum) which unites the two 
hemispheres. In the front part of this are seen the thin 
membranes (septum lutidum) which inclose between them 



Corpus Callosum 



Foramen of Monro 

Third Ventricle 

\ Pinqal Body 

I Cerebrum 




Optic Chiasma 

Pituitary Body / / / 

Oculomotor' Nerve / / / / 
PonsVarotii /' / 

Aqueduct / , 
Medulla Oblongata / 
fourth Ventricle 



Corpora 
Quadrigemina 

Cerebellum 



Spinal Cord 



FIG. 50. Section of Brain. 

a portion actually outside the brain, but often called the 
" fifth " ventricle. Below this is the fornix, which forms the 
roof of a true brain cavity the third ventricle whose 
sides are the optic thalami. This ventricle projects forward 
into a funnel called the infundibulum. In the center of this 
ventricle is a round body (the median commissure) which 
was cut through by the section. In front of this is a small 
aperture (the foramen of Monro) that connects this cavity 
frith a cavity in the right hemisphere. The floor of the third 



NERVOUS SYSTEM 107 

ventricle is formed by the crura cerebri, which extend back- 
ward, between the pons and the cerebellum, into the spinal 
bulb or medulla, and this, in turn, Backward into the spinal 
cord. At the back of the third ventricle note that a tube or 
canal (aqueduct) connects it with a much smaller cavity (the 
fourth ventricle) just under the cerebellum. Four little bodies 
(the corpora quadrigemina) form the roof of this tube between 
the fornix and the cerebellum. Note the treelike internal 
structure of the cerebellum. What causes its wrinkled 
surface? 

Note the gray and the white matter that make up the 
cerebrum. Where is the gray matter located? the white? 

NOTE. The first ventricle in the olfactory lobes and the lateral 
ventricle may be shown by suitable sections, if desired, and the re- 
lation of these may be brought out by the aid of diagrams of a 
simple brain structure. 

LXIX. DISSECTION OF SPINAL COR: 

Apparatus. Thin section of cervical portion of spinal cord, 
glycerine, slides, cover glass, compound microscope. 

Directions. (Prepare sections by placing a piece of the 
cervical spinal cord for three or four weeks in Miiller's fluid 
[2| parts of potassium bichromate, 1 part of sodium sulphate, 
100 parts of water]. Then wash it with water and place it 
in 30 % alcohol for a few days. Then transfer it to 95 % 
alcohol. Cut a thin cross section and mount it in glycerine. 
Cover it with a cover glass). 

Examine under the low power. Note the outer covering 
of pia mater. Note the distribution of the gray and white 
matter. Sketch it. Is it the same as in the brain? Note 
the division into two parts by a deep anterior, and a shal- 
low posterior fissure. Note also two fissures in each half (an^ 




108 



EXPERIMENTAL PHYSIOLOGY 



terior and posterior lateral) through which the central gray 
mass reaches the surface. The gray masses in each half of 
the cord may be seen to be united by a commissure that 
incloses the central or neural canal. Note the cellular char- 
acter of the gray matten The gray matter that forms the 




FIG. 51. 

posterior horns forms the core of spinal nerves of the sort 
called afferent. The anterior horns form the core of effer- 
ent nerves. (Afferent nerves carry messages to the cord; 
efferent, away from it.) The white matter covers these and 
they unite outside in a common spinal nerve. (See Fig. 51.) 
For structure of a neuron, see Ex. XXXI. 



SPECIAL SENSES 



LXX. NERVE ACTION 

Apparatus. A stop watch, pencil, paper. 

Directions. Let the teacher write a vowel on a piece of 
paper which he shall keep covered. Arrange the class in a 
circle. Station a boy beside the teacher with a stop watch. 
Proceed as follows: The teacher shows the vowel to the 
pupil on his right, who whispers it to the pupil on his right as 
quickly as possible, and so on around the circle to the teacher 
again. All this as rapidly as possible. Let the boy with 
the watch release the stop at the second when the teacher 
exposes the letter to the pupil on his right, and stop it again 
when the last pupil repeats the letter to the teacher. , Divide 
the time elapsed by the number of pupils. The result will 
represent the average reaction time of each pupil. Change 
the arrangement of the pupils and note whether the time 
varies. What muscular action does each pupil perform in 
receiving and transmitting the sound? What sensory nerves 
are employed? what motor nerves? 

NOTE. In order to bring out various sensation reactions this ex- 
periment may be varied in many ways which will suggest themselves 
to the teacher. 

LXXI. CUTANEOUS SENSATIONS ^\ 

Apparatus. A pair of metal compasses, toothpicks, a dish of 
boiling water, a dish of ice water, pen and ink. 

Directions. One pupil should operate, while another acts 
as subject. The subject should be blindfolded. 

109 



110 EXPERIMENTAL PHYSIOLOGY 

A. Touch. Sharpen the ends of the toothpicks and tie 
one to each arm of the compass. What is the least 
distance apart at which the two points may be held and 
felt as two points, when applied to the tips of the fingers? 
the tip of the tongue? back of the hand? forearm? back 
of the neck? Record the results. Are all parts of the 
body equally sensitive to touch? Which parts are most 
sensitive? 

B. Temperature. Dip a metal point of the compasses in 
cold water and move it lightly over the back of the hand. 
Does it feel equally cold to all parts of the skin? Mark 
with an ink dot those points where the sensation is most 
acute. Now heat the metal point in the hot water and 
move it over the same area. Locate, as before, the spots 
where sensation is most acute. Do the hot and cold spots 
coincide? What do you conclude about the temperature 
sensation power of the skin? Is it a general or a local- 
ized sensitive power? Test other areas of the body in 
the same way. Are the temperature spots equally numer- 
ous in all parts? Where are they most numerous? least 
numerous? 

LXXIL STUDY OF THE TONGUE 

Directions. Protrude the tongue as far as possible and 
with the aid of a mirror examine its surface. Note the 
raised points (the papillce) on the surface. Observe that 
they are of three forms: long and slender (filiform), 
mushroom-topped (fungiform), and large and wartlike 
(circumvallate). Draw an outline of the tongue and 
locate on it the regions where these different forms are to 
be found. 





SPECIAL SENSES 

LXXIIL SENSATIONS OF TASTE AND SMELL 

Apparatus. Onion, sugar, salt, vinegar, dilute ammonia, quinine, 
vanilla or other flavor. 

Directions. A. Location of Taste. Wipe the tongue and 
place on its tip a little dry sugar. Has it any taste? Let it 
dissolve^ Has it any taste nowfllepeat, placing the sugar 
at the back of the tongue. Is its sweetness more or less 
prominent? Repeat again, using quinine, vinegar, and salt 
successively. Where are the sensations of bitterness, sour- 
ness, and saltiness most prominent? 

B. Taste and Odor. Examine the various substances 
named under " Apparatus. " Which have taste? odor? 
Place each of these substances on the tongue of a pupil 
who has been previously blindfolded, and who is holding 
his nose tightly. Record the substances recognized by taste 
alone. Repeat, leaving the nose free but retaining the 
blindfold. Record those substances recognized by smell 
alone; by taste and smell combined. 



LXXIV. HEARING; LAWS OF SOUND (OPTIONAL) 
Apparatus. Stretched wire, bridge to shorten length. 

Directions. A. Strike the wire. Do you get any 
sound ? What is the wire doing? All sound depends 
upon vibration: test several sounding bodies to verify this 
statement. 

B. Move the bridge to the middle point of the wire and 
strike again. Is the pitch higher or lower? Does a short 
string vibrate faster or slower than a long one? What effect 
has rate of vibration on the pitch of a sound? 

C. Strike the wire gently. Note the distance at which 
the sound can be heard. Strike harder. Is the tone louder 



112 EXPEKIMENTAL PHYSIOLOGY 

or softer? Can it be heard at a farther distance? Does it 
vary in pitch? What effect on sound does extent (ampli- 
tude) of vibration have? 

D. Stand at the point where you can just hear the tick- 
ing of a watch. Now make a conical tube of paper and 
insert the small end in the ear. Point the larger end toward 
the watch. Can you hear it any better now? What part 
of the ear serves a purpose similar to that of the tube? 

E. Sympathetic Vibrations. Tune two wires to the same 
pitch. Place a paper rider on one and strike the other. 
What happens to the rider? Lower the pitch of one wire and 
repeat. Is the result the same? 

LXXV. VISION; DISSECTION OF SHEEP'S EYE 

Apparatus. Sheep's skull with eyes in socket (the skull used 
in Ex. LXVIII will serve for this purpose), scalpel, scissors, bone 
forceps, evaporating dish. 

Directions. Cut away, with the bone forceps, the bones 
that inclose the eye, so that it may be seen in position from 
the side. 

A. Muscles. Notice that the motion of the eyeball is 
controlled by six muscular bands. Locate the attachment 
of four of these bands on the top (superior rectus), bottom 
(inferior rectus), side near nose (internal rectus), and side 
farthest from nose (external rectus). Note that these ex- 
tend directly backward to the end of the socket and have 
their origin there. What motions do these muscles give to 
the eyeball? Now locate on the top of the eyeball the at- 
tachment of a transverse band of muscle (the superior 
oblique) and follow its course, through a tendon pulley, to 
its origin at the back of the socket. In what direction 
does its contraction take place? What motion does it give 



SPECIAL SENSES 113 

to the eye? On the under side of the eye locate another 
transverse muscle (the inferior oblique). Where is its ori- 
gin? Has it a pulley? 

B. The Externals of the Eye. Cut the muscle bands and 
trim away a white membrane (the conjunctiva, a continua- 
tion of the lining of the eyelid) in the front of the eye. Note 
that the eye is still attached to the socket by a cord, just 
below and outside the center of its rear surface. This is the 
optic nerve, which enters the eye here from the brain. Pull 
the eye out of the socket and cut this cord. Now examine 
the outside of the eyeball. Note that it is covered with a 
firm white coat (the sclerotic) except in the front, where there 
is a clear layer, the cornea, usually dulled in death. 

C. The Internals of the Eye. Hold the eye with the cornea 
uppermost, and remove this with the scalpel by cutting hori- 
zontally around its edge. The liquid back of this layer is 
the aqueous humor. Directly back of the cornea appears a 
circular muscular curtain colored in the human eye 
called the iris, and in its center a hole the pupil. What 
conclusions do you draw as to the functions of this iris from 
comparing the size of the pupil of your own eye, when look- 
ing at a bright light, with its size when in a dimly lighted 
room? Is its action voluntary? 

Now lay the eye upon its side in the evaporating dish 
and cover it with water. With the scalpel cut a section 
through the entire eye, splitting the optic nerve (see Fig. 
52). Observe the following parts: just back of the iris 
the convex crystalline lens and its capsule; the muscles that 
control the shape of the lens the ciliary muscles and 
their ligamentous attachment (suspensory ligament); on the 
inside of the layers that form the walls of the eye, at the edge 
of the lens, a black, ridged membrane (the ciliary process)' 



114 EXPERIMENTAL PHYSIOLOGY 

the jellylike mass that fills the body of the eye (vitreous 
humor) ; the three layers of the wall of the eyeball, outer 
(sclerotic), middle (choroid), inner (retina). 

Note that the optic nerve pierces the two outer coats 
and spreads out to form the retina. Remove the vitreous 
humor and notice the soft, whitish retina. Tear this out 




CP 



FIQ. 52. Cross Section of the Eye: Con, conjunctiva; Sc, sclerotic; C, cornea; A, 
aqueous humor; 7, iris; L, crystalline lens; Cm, ciliary muscles and ligament; CP, 
ciliary process; V, vitreous humor; Ch, choroid; R, retina; O, optic nerve. 

with the forceps and note its consistency and thickness. 
Under this observe the color and luster of the choroid coat. 
When this is torn out, the interlacing blood vessels are seen 
passing from one layer to the other. 

LXXVI. ACTION OF THE EYE 

Apparatus. Model of eye. 

Directions. Construct a model of the eye as follows: 
Obtain a wooden box eighteen or twenty inches long and 



SPECIAL SENSES 



115 



about eight inches wide and deep. Leaving one side open, 
paint the inside of the box black. Around the open side 
tack a piece of black cloth large enough to cover the head 
of the observer and shut out the light from the interior of 
the box. At one end of the box cut a hole one inch in di- 
ameter. Cut several black cardboard disks to fit this aper- 
ture, and perforate the center of each with holes varying 
from one-sixteenth to one-half inch in diameter. Mount a 
convex lens in a movable holder which can be moved for- 
ward and backward on the floor of the box, and which will 
bring the center of the lens opposite the center of the hole. 



Diap) 


ragm (Iris) Screw 


i (Retina) $ 




Lens 




A 
I 


/ 

*! 


\ 
t 




1 


| 


i 




1 


^ 


, 




1 gggg^JA 


w>^^m \ 







FIG. 53. 

Mount a piece of ground glass in the same way to serve as a 
screen. Arrange all parts as in Fig. 53. 

The cardboard disks will then correspond to the iris with 
its pupil; the walls of the box to the sclerotic; the black 
paint to the choroid (what is its function?); the lens to the 
crystalline lens, and the screen to the retina. A watch glass 
placed on the aperture would resemble the cornea. 

A. Action of Parts. Darken the room and place a lighted 
candle at a distance of three feet from the aperture. Place 
in the aperture the disk with one-quarter inch perforation. 
Cover head with cloth and place screen at the rear of the 
box. Now move the lens back and forth until there ap- 



116 EXPERIMENTAL PHYSIOLOGY 

pears on the screen a sharp image of the candle flame. Is 
it right side up? What is the function of the lens? Mark 
position of lens and screen. Move the candle three feet 
farther away. Does the image remain on the screen? Keep- 
ing the lens fixed, move the screen forward in the box until 
the distinct image appears again. Return the screen to its 
original position and, by moving the lens, cause the same 
result an image on the screen. Which is adjustable in 
the eye the screen (retina) or lens? How is the lens ad- 
justed in the eye? (This adjustment of the lens to the dis- 
tance of objects is called accommodation.) Change the disks 
in the aperture, using first larger and then smaller openings. 
Which gives the brightest image? What is the function of 
the iris? 

NOTE. By using external lenses as " spectacles," shortsightedness 
and longsightedness can be correcte'd and illustrated. 



COLUfit 
PHARMACY 



BACTERIA 



&Y** 



LXXVII. STUDY OF BACTERIA 

Apparatus. Culture medium (agar, 5 g.; 1 Liebig beef extract, 
5 g.; Peptone, 5 g.; salt, 5 g.; water, 500 c.c.), 2 sterilized Petri dishes 
and test tubes, compound microscope, microscope slides, cover glasses, 
prepared slides of coccus, bacillus, spirillum, etc., forms, needle points, 
gentian violet stain, litmus paper. 

Directions. A . To Demonstrate the Presence of Bacteria 
in Air. Take two Petri dishes containing cooled culture 
medium. Examine, and note the transparent character of 
the medium. Now remove the cover of one of the dishes 
and allow it to remain exposed to the air of the room for .ten 
minutes. At the end of that time recover it and set aside 
in a temperature of 36 C. Keep the cover on the second 
dish (control) and set it aside with the first dish. (N.B. 
Other dishes prepared in the same way may be exposed in 
various places to give variety and comparative results.) 
Examine these dishes from day to day until spots appear on 
their surface. Describe the color and appearance of these 

* Agar makes a firmer jelly and is better for general use. In case it 
is not available gelatin may be used. In that case take 50 g. of gelatin. 

2 First dissolve in water all the ingredients except the agar and neu- 
tralize with sodium carbonate if necessary. Next dissolve the agar in 
boiling water and add, with stirring, the first solution. Neutralize 
again with sodium carbonate if necessary. Make up to 500 c.c. with 
water, boil and filter hot through absorbent cotton. Pour this hot 
liquid into sterilized Petri dishes and test tubes as desired. Cover the 
dishes and plug the ends of the test tubes with sterilized absorbent cotton. 

117 



118 EXPERIMENTAL PHYSIOLOGY 

spots. Then with the needle point remove some of the 
spots to a slide, cover with a glass, run a little water under 
the glass, and examine under the high power of the com- 
pound microscope. Describe with drawings what you see. 
Smear a little of one of the spots on a cover glass and pass 
the glass through a gas flame two or three times until dry. 
Mount the glass, smear side down, on a microscope slide. 
Run a little gentian violet under the cover glass and after a 
few minutes examine again. What effect has the stain? l 

Do spots appear on the control dish? What does this 
prove as to the origin of the bacteria? Are the bacteria all 
alike in size and shape? Do all or any of them move? Are 
the spots all alike in color and shape? Examine several as 
above and report your results with drawings of the forms 
observed. 

Write a detailed statement telling what you have learned 
about bacteria from this experiment. 

B. To Demonstrate the Presence of Bacteria in Water. 
Take two test tubes containing culture medium. Pour into 
one 10 c.c. of ordinary drinking water and plug with ster- 
ilized cotton. Boil some water and pour 10 c.c. into the 
second tube. Plug in same way as first. Place both tubes 
at 36 C. and let stand several days. At the end of that time 
examine both tubes. Describe the difference in appearance, 
odor, reaction to litmus. Examine a drop of the water from 
each on a microscope slide. Record the results with drawings. 
Why does boiling water prevent infection? 

C. To Demonstrate the Forms of Bacteria. Examine pre- 
pared slides of various types of bacteria and make drawings 
of same. 

D. Variations of the Above Experiments. 

1 Bacteria do not stain readily until killed by heat or other means. 



BACTERIA 119 

(a) Conditions favorable and unfavorable to growth may 
be determined by modifications of B. 

(6) Protection from dust may be shown as a modification 
of A. 

(c) Other substances may be substituted for water in B. 

(d) The preparation of pure cultures may be shown by 
transferring to new dishes the colonies obtained in A. 

(e) Examination for disease germs may be demonstrated 
by transferring mucus from throat, dirt from finger nails, 
blood, etc., to prepared dishes and examining the results as 
described in A and B. 




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have fully established. 

^j The topics are taken up in the text in their logical order. 
The treatment begins with an elementary agricultural chem- 
istry, in which are discussed the elements that are of chief 
importance in plant and animal life. Following in turn are 
sections on soils and fertilizers ; agricultural botany ; economic 
plants, including field and forage crops, fruits and vege- 
tables; plant diseases; insect enemies; animal husbandry; and 
farm management. 

^| The chapter on plant diseases, by Dr. E. M. Freeman, 
Professor of Botany and Vegetable Pathology, College of 
Agriculture, University of Minnesota, describes the various 
fungus growths that injure crops, and suggests methods of 
fighting them. The section on farm management treats farm- 
ing from the modern standpoint as a business proposition. 



AMERICAN BOOK COMPANY 

(324; 



DESCRIPTIVE 

CATALOGUE OF HIGH 

SCHOOL AND COLLEGE 

TEXTBOOKS 

Published Complete and in Sections 



WE issue a Catalogue of High School and College Text- 
books, which we have tried to make as valuable and 
as useful to teachers as possible. In this catalogue 
are set forth briefly and clearly the scope and leading charac- 
teristics of each of our best textbooks. In most cases there 
are also given testimonials from well-known teachers, which 
have been selected quite as much for their descriptive qualities 
as for their value as commendations. 

^j For the convenience of teachers this Catalogue is also 
published in separate sections treating of the various 
branches of study. These pamphlets are entitled : Eng- 
lish, Mathematics, History and Political Science, Science, 
Modern Foreign Languages, Ancient Languages, Com- 
mercial Subjects, and Philosophy and Education. A 
single pamphlet is devoted to the Newest Books in all 
subjects. 

*J| Teachers seeking the newest and best books for their 
classes are invited to send for our Complete High School and 
College Catalogue, or for such sections as may be of greatest 
interest. 

^[ Copies of our price lists, or of special circulars, in which 
these books are described at greater length than the space 
limitations of the catalogue permit, will be mailed to any 
address on request. 

^| All correspondence should be addressed to the nearest 
of the following offices of the company: New York, Cincin- 
nati, Chicago, Boston, Atlanta, San Francisco. 



AMERICAN BOOK COMPANY 

(3")